diff --git a/Sources/geometrize-cli/main.swift b/Sources/geometrize-cli/main.swift
index e4660dd..871370c 100644
--- a/Sources/geometrize-cli/main.swift
+++ b/Sources/geometrize-cli/main.swift
@@ -9,6 +9,7 @@ struct GeometrizeOptions: ParsableArguments {
     @Option(name: .shortAndLong, help: "Output file pathname.") var outputPath: String
     @Option(name: [.customShort("t"), .long], help: "White space separated list of shapes to use geometrizing image.") var shapeTypes: String = "rectangle"
     @Option(name: [.customShort("c"), .long], help: "The number of shapes to generate for the final output.") var shapeCount: UInt?
+    @Option(name: [.customShort("w"), .long], help: "Width of lines, polylines, bezier curves.") var lineWidth: UInt?
     @Flag(name: .shortAndLong, help: "Verbose output.") var verbose: Bool = false
 }
 
@@ -90,8 +91,11 @@ print("Using shapes: \(shapeTypes.map { "\(type(of: $0))".dropLast(5) /* drop .T
 
 let shapeCount: Int = Int(options.shapeCount ?? 100)
 
+let strokeWidth: Int = Int(options.lineWidth ?? 1)
+
 let runnerOptions = ImageRunnerOptions(
     shapeTypes: shapeTypes,
+    strokeWidth: strokeWidth,
     alpha: 128,
     shapeCount: 100,
     maxShapeMutations: 100,
@@ -108,7 +112,7 @@ var runner = ImageRunner(targetBitmap: targetBitmap)
 var shapeData: [ShapeResult] = []
 
 // Hack to add a single background rectangle as the initial shape
-let rect = Rectangle(x1: 0, y1: 0, x2: Double(targetBitmap.width), y2: Double(targetBitmap.height))
+let rect = Rectangle(strokeWidth: 1, x1: 0, y1: 0, x2: Double(targetBitmap.width), y2: Double(targetBitmap.height))
 shapeData.append(ShapeResult(score: 0, color: targetBitmap.averageColor(), shape: rect))
 
 var counter = 0
diff --git a/Sources/geometrize/ImageRunner.swift b/Sources/geometrize/ImageRunner.swift
index 022a6ce..4488380 100644
--- a/Sources/geometrize/ImageRunner.swift
+++ b/Sources/geometrize/ImageRunner.swift
@@ -34,6 +34,9 @@ public struct ImageRunnerOptions {
     /// The shape types that the image runner shall use.
     var shapeTypes: [Shape.Type]
 
+    /// Width of Line, Polyline, QuadraticBezier
+    var strokeWidth: Int
+
     /// The alpha/opacity of the shapes (0-255).
     var alpha: UInt8
 
@@ -53,8 +56,20 @@ public struct ImageRunnerOptions {
     /// If zero or do not form a rectangle, the entire target image is used i.e. (0, 0, imageWidth, imageHeight).
     var shapeBounds: ImageRunnerShapeBoundsOptions
 
-    public init(shapeTypes: [Shape.Type], alpha: UInt8, shapeCount: Int, maxShapeMutations: Int, seed: Int, maxThreads: Int, shapeBounds: ImageRunnerShapeBoundsOptions) {
+    public init(
+        shapeTypes: [Shape.Type],
+        strokeWidth: Int,
+        alpha: UInt8,
+        shapeCount: Int,
+        maxShapeMutations: Int,
+        seed: Int,
+        maxThreads: Int,
+        shapeBounds: ImageRunnerShapeBoundsOptions
+    ) {
+        precondition(strokeWidth > 0)
+
         self.shapeTypes = shapeTypes
+        self.strokeWidth = strokeWidth
         self.alpha = alpha
         self.shapeCount = shapeCount
         self.maxShapeMutations = maxShapeMutations
@@ -98,7 +113,7 @@ public struct ImageRunner {
     ) -> ShapeResult? {
         let types = options.shapeTypes
 
-        let shapeCreator: ShapeCreator = shapeCreator ?? makeDefaultShapeCreator(types: types)
+        let shapeCreator: ShapeCreator = shapeCreator ?? makeDefaultShapeCreator(types: types, strokeWidth: Double(options.strokeWidth))
 
         model.setSeed(options.seed)
 
diff --git a/Sources/geometrize/SVGExporter.swift b/Sources/geometrize/SVGExporter.swift
index df3d3f8..98934d6 100644
--- a/Sources/geometrize/SVGExporter.swift
+++ b/Sources/geometrize/SVGExporter.swift
@@ -40,7 +40,7 @@ public struct SVGExporter {
 
         if shape.self is Line || shape.self is Polyline || shape.self is QuadraticBezier {
             styles += strokeAttrib(color: color)
-            styles += " stroke-width=\"1\" fill=\"none\" "
+            styles += " stroke-width=\"\(Int(shape.strokeWidth))\" fill=\"none\" "
             styles += strokeOpacityAttrib(color: color)
         } else {
             styles += fillAttrib(color: color)
diff --git a/Sources/geometrize/ShapeCreator.swift b/Sources/geometrize/ShapeCreator.swift
index cb355ef..08327c6 100644
--- a/Sources/geometrize/ShapeCreator.swift
+++ b/Sources/geometrize/ShapeCreator.swift
@@ -6,13 +6,13 @@ public typealias ShapeCreator = (inout SplitMix64) -> any Shape
 /// - Parameters:
 ///   - types: The types of shapes to create.
 /// - Returns: The default shape creator.
-public func makeDefaultShapeCreator(types: [Shape.Type]) -> ShapeCreator {
+public func makeDefaultShapeCreator(types: [Shape.Type], strokeWidth: Double) -> ShapeCreator {
     return { generator in
         let index = types.index(
             types.startIndex,
             offsetBy: Int._random(in: 0...types.count - 1, using: &generator)
         )
         let shapeType = types[index]
-        return shapeType.init()
+        return shapeType.init(strokeWidth: strokeWidth)
     }
 }
diff --git a/Sources/geometrize/Shapes/Circle.swift b/Sources/geometrize/Shapes/Circle.swift
index 32b4650..2a31cc2 100644
--- a/Sources/geometrize/Shapes/Circle.swift
+++ b/Sources/geometrize/Shapes/Circle.swift
@@ -1,24 +1,27 @@
 import Foundation
 
 public final class Circle: Shape {
+    public var strokeWidth: Double
     public var x: Double // x-coordinate.
     public var y: Double // y-coordinate.
     public var r: Double // Radius.
 
-    public init() {
+    public init(strokeWidth: Double) {
+        self.strokeWidth = strokeWidth
         x = 0.0
         y = 0.0
         r = 0.0
     }
 
-    public init(x: Double, y: Double, r: Double) {
+    public init(strokeWidth: Double, x: Double, y: Double, r: Double) {
+        self.strokeWidth = strokeWidth
         self.x = x
         self.y = y
         self.r = r
     }
 
     public func copy() -> Circle {
-        Circle(x: x, y: y, r: r)
+        Circle(strokeWidth: strokeWidth, x: x, y: y, r: r)
     }
 
     public func setup(x xRange: ClosedRange<Int>, y yRange: ClosedRange<Int>, using generator: inout SplitMix64) {
diff --git a/Sources/geometrize/Shapes/Ellipse.swift b/Sources/geometrize/Shapes/Ellipse.swift
index 52e13c4..9ef498c 100644
--- a/Sources/geometrize/Shapes/Ellipse.swift
+++ b/Sources/geometrize/Shapes/Ellipse.swift
@@ -1,19 +1,22 @@
 import Foundation
 
 public final class Ellipse: Shape {
+    public var strokeWidth: Double
     public var x: Double // x-coordinate.
     public var y: Double // y-coordinate.
     public var rx: Double // x-radius.
     public var ry: Double // y-radius.
 
-    public init() {
+    public init(strokeWidth: Double) {
+        self.strokeWidth = strokeWidth
         x = 0.0
         y = 0.0
         rx = 0.0
         ry = 0.0
     }
 
-    public init(x: Double, y: Double, rx: Double, ry: Double) {
+    public init(strokeWidth: Double, x: Double, y: Double, rx: Double, ry: Double) {
+        self.strokeWidth = strokeWidth
         self.x = x
         self.y = y
         self.rx = rx
@@ -21,7 +24,7 @@ public final class Ellipse: Shape {
     }
 
     public func copy() -> Ellipse {
-        Ellipse(x: x, y: y, rx: rx, ry: ry)
+        Ellipse(strokeWidth: strokeWidth, x: x, y: y, rx: rx, ry: ry)
     }
 
     public func setup(x xRange: ClosedRange<Int>, y yRange: ClosedRange<Int>, using generator: inout SplitMix64) {
diff --git a/Sources/geometrize/Shapes/Line.swift b/Sources/geometrize/Shapes/Line.swift
index 1adc5e2..749ff64 100644
--- a/Sources/geometrize/Shapes/Line.swift
+++ b/Sources/geometrize/Shapes/Line.swift
@@ -1,16 +1,19 @@
 import Foundation
 
 public final class Line: Shape {
+    public var strokeWidth: Double
     public var x1, y1, x2, y2: Double
 
-    public init() {
+    public init(strokeWidth: Double) {
+        self.strokeWidth = strokeWidth
         x1 = 0.0
         y1 = 0.0
         x2 = 0.0
         y2 = 0.0
     }
 
-    public init(x1: Double, y1: Double, x2: Double, y2: Double) {
+    public init(strokeWidth: Double, x1: Double, y1: Double, x2: Double, y2: Double) {
+        self.strokeWidth = strokeWidth
         self.x1 = x1
         self.y1 = y1
         self.x2 = x2
@@ -18,7 +21,7 @@ public final class Line: Shape {
     }
 
     public func copy() -> Line {
-        Line(x1: x1, y1: y1, x2: x2, y2: y2)
+        Line(strokeWidth: strokeWidth, x1: x1, y1: y1, x2: x2, y2: y2)
     }
 
     public func setup(x xRange: ClosedRange<Int>, y yRange: ClosedRange<Int>, using generator: inout SplitMix64) {
@@ -49,7 +52,7 @@ public final class Line: Shape {
 
     public func rasterize(x xRange: ClosedRange<Int>, y yRange: ClosedRange<Int>) -> [Scanline] {
         let lines =
-            drawThickLine(from: Point(x: Int(x1), y: Int(y1)), to: Point(x: Int(x2), y: Int(y2)))
+            drawThickLine(from: Point(x: Int(x1), y: Int(y1)), to: Point(x: Int(x2), y: Int(y2)), thickness: Int(strokeWidth))
             .compactMap {
                 Scanline(y: $0.y, x1: $0.x, x2: $0.x).trimmed(x: xRange, y: yRange)
             }
diff --git a/Sources/geometrize/Shapes/Polyline.swift b/Sources/geometrize/Shapes/Polyline.swift
index 4965d47..8371820 100644
--- a/Sources/geometrize/Shapes/Polyline.swift
+++ b/Sources/geometrize/Shapes/Polyline.swift
@@ -1,18 +1,21 @@
 import Foundation
 
 public final class Polyline: Shape {
+    public var strokeWidth: Double
     public var points: [Point<Double>]
 
-    public init() {
+    public init(strokeWidth: Double) {
+        self.strokeWidth = strokeWidth
         points = []
     }
 
-    public init(points: [Point<Double>]) {
+    public init(strokeWidth: Double, points: [Point<Double>]) {
+        self.strokeWidth = strokeWidth
         self.points = points
     }
 
     public func copy() -> Polyline {
-        Polyline(points: points)
+        Polyline(strokeWidth: strokeWidth, points: points)
     }
 
     public func setup(x xRange: ClosedRange<Int>, y yRange: ClosedRange<Int>, using generator: inout SplitMix64) {
@@ -49,7 +52,7 @@ public final class Polyline: Shape {
         for i in 0..<points.count {
             let p0 = points[i]
             let p1 = i < points.count - 1 ? points[i + 1] : p0
-            let points = drawThickLine(from: Point<Int>(p0), to: Point<Int>(p1))
+            let points = drawThickLine(from: Point<Int>(p0), to: Point<Int>(p1), thickness: Int(strokeWidth))
             for point in points {
                 if !duplicates.contains(point) {
                     duplicates.insert(point)
diff --git a/Sources/geometrize/Shapes/QuadraticBezier.swift b/Sources/geometrize/Shapes/QuadraticBezier.swift
index 4449544..f489c66 100644
--- a/Sources/geometrize/Shapes/QuadraticBezier.swift
+++ b/Sources/geometrize/Shapes/QuadraticBezier.swift
@@ -2,6 +2,7 @@ import Foundation
 import Algorithms
 
 public final class QuadraticBezier: Shape {
+    public var strokeWidth: Double
     public var x1: Double // First x-coordinate.
     public var y1: Double // First y-coordinate.
     public var x2: Double // Second x-coordinate.
@@ -9,7 +10,8 @@ public final class QuadraticBezier: Shape {
     public var cx: Double // Control point x-coordinate.
     public var cy: Double // Control point y-coordinate.
 
-    public init() {
+    public init(strokeWidth: Double) {
+        self.strokeWidth = strokeWidth
         cx = 0.0
         cy = 0.0
         x1 = 0.0
@@ -18,7 +20,8 @@ public final class QuadraticBezier: Shape {
         y2 = 0.0
     }
 
-    public init(cx: Double, cy: Double, x1: Double, y1: Double, x2: Double, y2: Double) {
+    public init(strokeWidth: Double, cx: Double, cy: Double, x1: Double, y1: Double, x2: Double, y2: Double) {
+        self.strokeWidth = strokeWidth
         self.cx = cx
         self.cy = cy
         self.x1 = x1
@@ -28,7 +31,7 @@ public final class QuadraticBezier: Shape {
     }
 
     public func copy() -> QuadraticBezier {
-        QuadraticBezier(cx: cx, cy: cy, x1: x1, y1: y1, x2: x2, y2: y2)
+        QuadraticBezier(strokeWidth: strokeWidth, cx: cx, cy: cy, x1: x1, y1: y1, x2: x2, y2: y2)
     }
 
     public func setup(x xRange: ClosedRange<Int>, y yRange: ClosedRange<Int>, using generator: inout SplitMix64) {
@@ -72,7 +75,7 @@ public final class QuadraticBezier: Shape {
         // Prevent scanline overlap, it messes up the energy functions that rely on the scanlines not intersecting themselves
         var duplicates: Set<Point<Int>> = Set()
         for (from, to) in points.adjacentPairs() {
-            for point in drawThickLine(from: from, to: to) {
+            for point in drawThickLine(from: from, to: to, thickness: Int(strokeWidth)) {
                 if !duplicates.contains(point) {
                     duplicates.insert(point)
                     if let trimmed = Scanline(y: point.y, x1: point.x, x2: point.x).trimmed(x: xRange, y: yRange) {
diff --git a/Sources/geometrize/Shapes/Rectangle.swift b/Sources/geometrize/Shapes/Rectangle.swift
index 1808bc8..7a43827 100644
--- a/Sources/geometrize/Shapes/Rectangle.swift
+++ b/Sources/geometrize/Shapes/Rectangle.swift
@@ -2,16 +2,19 @@ import Foundation
 
 // Represents a rectangle.
 public final class Rectangle: Shape {
+    public var strokeWidth: Double
     public var x1, y1, x2, y2: Double
 
-    required public init() {
+    required public init(strokeWidth: Double) {
+        self.strokeWidth = strokeWidth
         x1 = 0.0
         y1 = 0.0
         x2 = 0.0
         y2 = 0.0
     }
 
-    public init(x1: Double, y1: Double, x2: Double, y2: Double) {
+    public init(strokeWidth: Double, x1: Double, y1: Double, x2: Double, y2: Double) {
+        self.strokeWidth = strokeWidth
         self.x1 = x1
         self.y1 = y1
         self.x2 = x2
@@ -20,11 +23,11 @@ public final class Rectangle: Shape {
 
     // Rectangle taking whole size of canvas
     public convenience init(canvasWidth width: Int, height: Int) {
-        self.init(x1: 0.0, y1: 0.0, x2: Double(width), y2: Double(height))
+        self.init(strokeWidth: 1, x1: 0.0, y1: 0.0, x2: Double(width), y2: Double(height))
     }
 
     public func copy() -> Rectangle {
-        Rectangle(x1: x1, y1: y1, x2: x2, y2: y2)
+        Rectangle(strokeWidth: strokeWidth, x1: x1, y1: y1, x2: x2, y2: y2)
     }
 
     public func setup(x xRange: ClosedRange<Int>, y yRange: ClosedRange<Int>, using generator: inout SplitMix64) {
diff --git a/Sources/geometrize/Shapes/RotatedEllipse.swift b/Sources/geometrize/Shapes/RotatedEllipse.swift
index 48ae679..044b0c2 100644
--- a/Sources/geometrize/Shapes/RotatedEllipse.swift
+++ b/Sources/geometrize/Shapes/RotatedEllipse.swift
@@ -2,13 +2,15 @@ import Foundation
 
 // Represents a rotated ellipse.
 public final class RotatedEllipse: Shape {
+    public var strokeWidth: Double
     public var x: Double // x-coordinate.
     public var y: Double // y-coordinate.
     public var rx: Double // x-radius.
     public var ry: Double // y-radius.
     public var angleDegrees: Double // Rotation angle in degrees.
 
-    public required init() {
+    public required init(strokeWidth: Double) {
+        self.strokeWidth = strokeWidth
         x = 0.0
         y = 0.0
         rx = 0.0
@@ -16,7 +18,8 @@ public final class RotatedEllipse: Shape {
         angleDegrees = 0.0
     }
 
-    public init(x: Double, y: Double, rx: Double, ry: Double, angleDegrees: Double) {
+    public init(strokeWidth: Double, x: Double, y: Double, rx: Double, ry: Double, angleDegrees: Double) {
+        self.strokeWidth = strokeWidth
         self.x = x
         self.y = y
         self.rx = rx
@@ -25,7 +28,7 @@ public final class RotatedEllipse: Shape {
     }
 
     public func copy() -> RotatedEllipse {
-        RotatedEllipse(x: x, y: y, rx: rx, ry: ry, angleDegrees: angleDegrees)
+        RotatedEllipse(strokeWidth: strokeWidth, x: x, y: y, rx: rx, ry: ry, angleDegrees: angleDegrees)
     }
 
     public func setup(x xRange: ClosedRange<Int>, y yRange: ClosedRange<Int>, using generator: inout SplitMix64) {
diff --git a/Sources/geometrize/Shapes/RotatedRectangle.swift b/Sources/geometrize/Shapes/RotatedRectangle.swift
index fef2ec7..d4a4440 100644
--- a/Sources/geometrize/Shapes/RotatedRectangle.swift
+++ b/Sources/geometrize/Shapes/RotatedRectangle.swift
@@ -2,13 +2,15 @@ import Foundation
 
 /// Represents a rotated rectangle.
 public final class RotatedRectangle: Shape {
+    public var strokeWidth: Double
     public var x1: Double
     public var y1: Double
     public var x2: Double
     public var y2: Double
     public var angleDegrees: Double
 
-    public required init() {
+    public required init(strokeWidth: Double) {
+        self.strokeWidth = strokeWidth
         x1 = 0.0
         y1 = 0.0
         x2 = 0.0
@@ -16,7 +18,8 @@ public final class RotatedRectangle: Shape {
         angleDegrees = 0.0
     }
 
-    public init(x1: Double, y1: Double, x2: Double, y2: Double, angleDegrees: Double) {
+    public init(strokeWidth: Double, x1: Double, y1: Double, x2: Double, y2: Double, angleDegrees: Double) {
+        self.strokeWidth = strokeWidth
         self.x1 = x1
         self.y1 = y1
         self.x2 = x2
@@ -25,7 +28,7 @@ public final class RotatedRectangle: Shape {
     }
 
     public func copy() -> RotatedRectangle {
-        RotatedRectangle(x1: x1, y1: y1, x2: x2, y2: y2, angleDegrees: angleDegrees)
+        RotatedRectangle(strokeWidth: strokeWidth, x1: x1, y1: y1, x2: x2, y2: y2, angleDegrees: angleDegrees)
     }
 
     public func setup(x xRange: ClosedRange<Int>, y yRange: ClosedRange<Int>, using generator: inout SplitMix64) {
diff --git a/Sources/geometrize/Shapes/Shape.swift b/Sources/geometrize/Shapes/Shape.swift
index d3d4f5f..9eecaf0 100644
--- a/Sources/geometrize/Shapes/Shape.swift
+++ b/Sources/geometrize/Shapes/Shape.swift
@@ -1,7 +1,9 @@
 import Foundation
 
 public protocol Shape: AnyObject, CustomStringConvertible {
-    init()
+    var strokeWidth: Double { get }
+
+    init(strokeWidth: Double)
 
     func copy() -> Self
 
diff --git a/Sources/geometrize/Shapes/Triangle.swift b/Sources/geometrize/Shapes/Triangle.swift
index eb2ecc3..39ba5d0 100644
--- a/Sources/geometrize/Shapes/Triangle.swift
+++ b/Sources/geometrize/Shapes/Triangle.swift
@@ -1,6 +1,7 @@
 import Foundation
 
 public final class Triangle: Shape {
+    public var strokeWidth: Double
     public var x1: Double // First x-coordinate.
     public var y1: Double // First y-coordinate.
     public var x2: Double // Second x-coordinate.
@@ -8,7 +9,8 @@ public final class Triangle: Shape {
     public var x3: Double // Third x-coordinate.
     public var y3: Double // Third y-coordinate.
 
-    public init() {
+    public init(strokeWidth: Double) {
+        self.strokeWidth = strokeWidth
         x1 = 0.0
         y1 = 0.0
         x2 = 0.0
@@ -17,7 +19,8 @@ public final class Triangle: Shape {
         y3 = 0.0
     }
 
-    public init(x1: Double, y1: Double, x2: Double, y2: Double, x3: Double, y3: Double) {
+    public init(strokeWidth: Double, x1: Double, y1: Double, x2: Double, y2: Double, x3: Double, y3: Double) {
+        self.strokeWidth = strokeWidth
         self.x1 = x1
         self.y1 = y1
         self.x2 = x2
@@ -27,7 +30,7 @@ public final class Triangle: Shape {
     }
 
     public func copy() -> Triangle {
-        Triangle(x1: x1, y1: y1, x2: x2, y2: y2, x3: x3, y3: y3)
+        Triangle(strokeWidth: strokeWidth, x1: x1, y1: y1, x2: x2, y2: y2, x3: x3, y3: y3)
     }
 
     public func setup(x xRange: ClosedRange<Int>, y yRange: ClosedRange<Int>, using generator: inout SplitMix64) {
diff --git a/Tests/geometrizeTests/BitmapDownsampleTests.swift b/Tests/geometrizeTests/BitmapDownsampleTests.swift
index aa31a2e..4bdba26 100644
--- a/Tests/geometrizeTests/BitmapDownsampleTests.swift
+++ b/Tests/geometrizeTests/BitmapDownsampleTests.swift
@@ -10,14 +10,14 @@ final class BitmapDownsampleTests: XCTestCase {
         var bitmap = Bitmap(width: width, height: height, color: .white)
         bitmap.draw(
             lines:
-                Ellipse(x: 250.0, y: 250.0, rx: 245.0, ry: 100.0)
+                Ellipse(strokeWidth: 1, x: 250.0, y: 250.0, rx: 245.0, ry: 100.0)
                 .rasterize(x: xRange, y: yRange),
             color:
                 .red.withAlphaComponent(200)
         )
         bitmap.draw(
             lines:
-                Ellipse(x: 250.0, y: 250.0, rx: 100.0, ry: 245.0)
+                Ellipse(strokeWidth: 1, x: 250.0, y: 250.0, rx: 100.0, ry: 245.0)
                 .rasterize(x: xRange, y: yRange),
             color:
                 .green.withAlphaComponent(200)
diff --git a/Tests/geometrizeTests/CircleTest.swift b/Tests/geometrizeTests/CircleTest.swift
index 2f98e9d..dca38a8 100644
--- a/Tests/geometrizeTests/CircleTest.swift
+++ b/Tests/geometrizeTests/CircleTest.swift
@@ -10,35 +10,35 @@ final class CircleTests: XCTestCase {
         var bitmap = Bitmap(width: width, height: height, color: .white)
         bitmap.draw(
             lines:
-                Circle(x: 250.0, y: 250.0, r: 275.0)
+                Circle(strokeWidth: 1, x: 250.0, y: 250.0, r: 275.0)
                 .rasterize(x: xRange, y: yRange),
             color:
                 .red
         )
         bitmap.draw(
             lines:
-                Circle(x: 330.0, y: 330.0, r: 250)
+                Circle(strokeWidth: 1, x: 330.0, y: 330.0, r: 250)
                 .rasterize(x: xRange, y: yRange),
             color:
                 .green.withAlphaComponent(200)
         )
         bitmap.draw(
             lines:
-                Circle(x: 0.0, y: 0.0, r: 133.5)
+                Circle(strokeWidth: 1, x: 0.0, y: 0.0, r: 133.5)
                 .rasterize(x: xRange, y: yRange),
             color:
                 .blue.withAlphaComponent(128)
         )
         bitmap.draw(
             lines:
-                Circle(x: 499.0, y: 0.0, r: 77.0)
+                Circle(strokeWidth: 1, x: 499.0, y: 0.0, r: 77.0)
                 .rasterize(x: xRange, y: yRange),
             color:
                 .magenta
         )
         bitmap.draw(
             lines:
-                Circle(x: 250.0, y: 250.0, r: 100.0)
+                Circle(strokeWidth: 1, x: 250.0, y: 250.0, r: 100.0)
                 .rasterize(x: xRange, y: yRange),
             color:
                 .cyan
diff --git a/Tests/geometrizeTests/CoreTests.swift b/Tests/geometrizeTests/CoreTests.swift
index 16fedf4..4a7c931 100644
--- a/Tests/geometrizeTests/CoreTests.swift
+++ b/Tests/geometrizeTests/CoreTests.swift
@@ -122,7 +122,7 @@ final class CoreTests: XCTestCase {
         var bitmapBuffer = Bitmap(stringLiteral: try String(contentsOf: Bundle.module.url(forResource: "hillClimb buffer bitmap", withExtension: "txt")!))
         let bitmapBufferOnExit = Bitmap(stringLiteral: try String(contentsOf: Bundle.module.url(forResource: "hillClimb buffer bitmap on exit", withExtension: "txt")!))
 
-        let rectangle = Rectangle(x1: 281, y1: 193, x2: 309, y2: 225)
+        let rectangle = Rectangle(strokeWidth: 1, x1: 281, y1: 193, x2: 309, y2: 225)
         // rectangle.setupImplementation = { r in
         //     r.setup(xMin: 0, yMin: 0, xMax: bitmapTarget.width, yMax: bitmapTarget.height)
         // }
@@ -136,7 +136,7 @@ final class CoreTests: XCTestCase {
 
         // hillClimb return state State(score: 0.162824, alpha: 128, shape: Rectangle(x1=272,y1=113,x2=355,y2=237))
 
-        let rectangleOnExit = Rectangle(x1: 272, y1: 113, x2: 355, y2: 237)
+        let rectangleOnExit = Rectangle(strokeWidth: 1, x1: 272, y1: 113, x2: 355, y2: 237)
         // rectangleOnExit.setupImplementation = { r in
         //     r.setup(xMin: 0, yMin: 0, xMax: bitmapTarget.width, yMax: bitmapTarget.height)
         // }
diff --git a/Tests/geometrizeTests/EllipseTests.swift b/Tests/geometrizeTests/EllipseTests.swift
index 1b6a354..f9bb0c1 100644
--- a/Tests/geometrizeTests/EllipseTests.swift
+++ b/Tests/geometrizeTests/EllipseTests.swift
@@ -10,14 +10,14 @@ final class EllipseTests: XCTestCase {
         var bitmap = Bitmap(width: width, height: height, color: .white)
         bitmap.draw(
             lines:
-                Ellipse(x: 250.0, y: 250.0, rx: 245.0, ry: 100.0)
+                Ellipse(strokeWidth: 1, x: 250.0, y: 250.0, rx: 245.0, ry: 100.0)
                 .rasterize(x: xRange, y: yRange),
             color:
                 .red.withAlphaComponent(200)
         )
         bitmap.draw(
             lines:
-                Ellipse(x: 250.0, y: 250.0, rx: 100.0, ry: 245.0)
+                Ellipse(strokeWidth: 1, x: 250.0, y: 250.0, rx: 100.0, ry: 245.0)
                 .rasterize(x: xRange, y: yRange),
             color:
                 .green.withAlphaComponent(200)
diff --git a/Tests/geometrizeTests/ImageRunnerTests.swift b/Tests/geometrizeTests/ImageRunnerTests.swift
index a03cf13..b4620da 100644
--- a/Tests/geometrizeTests/ImageRunnerTests.swift
+++ b/Tests/geometrizeTests/ImageRunnerTests.swift
@@ -20,6 +20,7 @@ final class ImageRunnerTests: XCTestCase {
 
         let options = ImageRunnerOptions(
             shapeTypes: [RotatedEllipse.self],
+            strokeWidth: 1,
             alpha: 128,
             shapeCount: 500,
             maxShapeMutations: 100,
@@ -36,7 +37,7 @@ final class ImageRunnerTests: XCTestCase {
         var shapeData: [ShapeResult] = []
 
         // Hack to add a single background rectangle as the initial shape
-        let rect = Rectangle(x1: 0, y1: 0, x2: Double(targetBitmap.width), y2: Double(targetBitmap.height))
+        let rect = Rectangle(strokeWidth: 1, x1: 0, y1: 0, x2: Double(targetBitmap.width), y2: Double(targetBitmap.height))
         shapeData.append(ShapeResult(score: 0, color: targetBitmap.averageColor(), shape: rect))
 
         var counter = 0
diff --git a/Tests/geometrizeTests/LineTests.swift b/Tests/geometrizeTests/LineTests.swift
index 7c3a089..3c658f8 100644
--- a/Tests/geometrizeTests/LineTests.swift
+++ b/Tests/geometrizeTests/LineTests.swift
@@ -11,9 +11,9 @@ final class LineTests: XCTestCase {
         var lines: [Scanline] = []
         let shift: Double = 10.0
         for x in stride(from: shift, through: Double(width) - shift, by: shift) {
-            lines += Line(x1: x, y1: shift, x2: Double(width) - shift, y2: Double(width) - shift)
+            lines += Line(strokeWidth: 1, x1: x, y1: shift, x2: Double(width) - shift, y2: Double(width) - shift)
                 .rasterize(x: xRange, y: yRange)
-            lines += Line(x1: x, y1: shift, x2: shift, y2: Double(height) - shift)
+            lines += Line(strokeWidth: 1, x1: x, y1: shift, x2: shift, y2: Double(height) - shift)
                 .rasterize(x: xRange, y: yRange)
         }
         bitmap.draw(lines: lines, color: .blue)
@@ -40,10 +40,10 @@ func scaleScanlinesTrimmed(width: Int, height: Int, step: Int, tickHeight: Int =
     lines += stride(from: 0, through: width, by: step)
         .map { i -> [Scanline] in
             let lines: [Scanline] =
-            Line(x1: Double(i - step / 5), y1: 0.0, x2: Double(i + step / 5), y2: 0.0)
+            Line(strokeWidth: 1, x1: Double(i - step / 5), y1: 0.0, x2: Double(i + step / 5), y2: 0.0)
                 .rasterize(x: xRange, y: yRange)
                 +
-            Line(x1: Double(i - step / 5), y1: yMaxDouble, x2: Double(i + step / 5), y2: yMaxDouble)
+            Line(strokeWidth: 1, x1: Double(i - step / 5), y1: yMaxDouble, x2: Double(i + step / 5), y2: yMaxDouble)
                 .rasterize(x: xRange, y: yRange)
             return lines
         }
@@ -51,10 +51,10 @@ func scaleScanlinesTrimmed(width: Int, height: Int, step: Int, tickHeight: Int =
     // Ticks on horizontal line
     lines += stride(from: step, to: width, by: step)
         .map { i -> [Scanline] in
-            Line(x1: Double(i), y1: 0.0, x2: Double(i), y2: tickHeightDouble)
+            Line(strokeWidth: 1, x1: Double(i), y1: 0.0, x2: Double(i), y2: tickHeightDouble)
                 .rasterize(x: xRange, y: yRange)
             +
-            Line(x1: Double(i), y1: Double(height - tickHeight - 1), x2: Double(i), y2: yMaxDouble)
+            Line(strokeWidth: 1, x1: Double(i), y1: Double(height - tickHeight - 1), x2: Double(i), y2: yMaxDouble)
                 .rasterize(x: xRange, y: yRange)
         }
         .flatMap { $0 }
@@ -62,10 +62,10 @@ func scaleScanlinesTrimmed(width: Int, height: Int, step: Int, tickHeight: Int =
     lines += stride(from: 0, through: height, by: step)
         .map { i -> [Scanline] in
             let lines: [Scanline] =
-            Line(x1: 0.0, y1: Double(i - step / 5), x2: 0.0, y2: Double(i + step / 5))
+            Line(strokeWidth: 1, x1: 0.0, y1: Double(i - step / 5), x2: 0.0, y2: Double(i + step / 5))
                 .rasterize(x: xRange, y: yRange)
             +
-            Line(x1: xMaxDouble, y1: Double(i - step / 5), x2: xMaxDouble, y2: Double(i + step / 5))
+            Line(strokeWidth: 1, x1: xMaxDouble, y1: Double(i - step / 5), x2: xMaxDouble, y2: Double(i + step / 5))
                 .rasterize(x: xRange, y: yRange)
             return lines
         }
@@ -73,10 +73,10 @@ func scaleScanlinesTrimmed(width: Int, height: Int, step: Int, tickHeight: Int =
     // Ticks on vertical line
     lines += stride(from: step, to: height, by: step)
         .map { i -> [Scanline] in
-            Line(x1: 0.0, y1: Double(i), x2: tickHeightDouble, y2: Double(i))
+            Line(strokeWidth: 1, x1: 0.0, y1: Double(i), x2: tickHeightDouble, y2: Double(i))
                 .rasterize(x: xRange, y: yRange)
             +
-            Line(x1: Double(width - tickHeight - 1), y1: Double(i), x2: xMaxDouble, y2: Double(i))
+            Line(strokeWidth: 1, x1: Double(width - tickHeight - 1), y1: Double(i), x2: xMaxDouble, y2: Double(i))
                 .rasterize(x: xRange, y: yRange)
         }
         .flatMap { $0 }
diff --git a/Tests/geometrizeTests/QuadraticBezierTests.swift b/Tests/geometrizeTests/QuadraticBezierTests.swift
index 2df39b2..47e7b73 100644
--- a/Tests/geometrizeTests/QuadraticBezierTests.swift
+++ b/Tests/geometrizeTests/QuadraticBezierTests.swift
@@ -10,7 +10,7 @@ final class QuadraticBezierTests: XCTestCase {
         var bitmap = Bitmap(width: width, height: height, color: .red)
         bitmap.draw(
             lines:
-                QuadraticBezier(cx: 327.0, cy: 295.0, x1: 57.0, y1: 542.0, x2: 190.0, y2: 216.0)
+                QuadraticBezier(strokeWidth: 1, cx: 327.0, cy: 295.0, x1: 57.0, y1: 542.0, x2: 190.0, y2: 216.0)
                 .rasterize(x: xRange, y: yRange),
             color:
                 .white
diff --git a/Tests/geometrizeTests/TriangleTests.swift b/Tests/geometrizeTests/TriangleTests.swift
index 7e0b4b7..f916ab6 100644
--- a/Tests/geometrizeTests/TriangleTests.swift
+++ b/Tests/geometrizeTests/TriangleTests.swift
@@ -10,14 +10,14 @@ final class TriangleTests: XCTestCase {
         var bitmap = Bitmap(width: width, height: height, color: .white)
         bitmap.draw(
             lines:
-                Triangle(x1: 20, y1: 20, x2: 480, y2: 300, x3: 100, y3: 480)
+                Triangle(strokeWidth: 1, x1: 20, y1: 20, x2: 480, y2: 300, x3: 100, y3: 480)
                 .rasterize(x: xRange, y: yRange),
             color:
                 .yellow
         )
         bitmap.draw(
             lines:
-                Triangle(x1: 510, y1: -10, x2: 250, y2: 505, x3: -5, y3: 270)
+                Triangle(strokeWidth: 1, x1: 510, y1: -10, x2: 250, y2: 505, x3: -5, y3: 270)
                 .rasterize(x: xRange, y: yRange),
             color:
                 .red.withAlphaComponent(128)