diff --git a/Week 3 - Data and Abstraction/Lecture 3.2 - How Classes Are Organized.md b/Week 3 - Data and Abstraction/Lecture 3.2 - How Classes Are Organized.md
index 5854ebd..0721014 100644
--- a/Week 3 - Data and Abstraction/Lecture 3.2 - How Classes Are Organized.md	
+++ b/Week 3 - Data and Abstraction/Lecture 3.2 - How Classes Are Organized.md	
@@ -10,25 +10,36 @@
 
 + In order to import a named type from a package we do:
 
-        import progfun.examples.Hello
-        import progfun.examples.{Hello, Rational}   // imports more than one
+        import progfun.examples.Hello               //named import 
+        import progfun.examples.{Hello, Rational}   // imports more than one, named import
         import progfun.examples._                   // imports everything under examples
 
-+ All members of the packages `scala`, `java.lang` and the singleton object `scala.Predef` are auto imported.
++ All members of the packages:
+- `scala` 
+- `java.lang` 
+- and the singleton object `scala.Predef` are auto imported.
 
 ### Traits
 + In Scala, a class can have only one superclass. It's a single inheritance language.
 + If a class wants to inherit code from more than one supertype we use `traits`.
 + `traits` are declared like an `abstract class` with the keyword  `trait` instead of `abstract class`
+```scala
+trait Planar {
+def height: Int
+def width: Int
+def surface = height * width
+}
+```
 + Classes, objects and traits can inherit from at most one class but from many traits.
+```scala
+class Square extends Shape with Planar with Movable
+```
 + Classes inherit code from a trait with the `with` keyword.
 
-        class Square extends Shape with Planar with Movable
-
 + traits cannot have `val` parameters. But unlike interfaces in Java it can contain concrete methods and fields.
 
 ### Scala class hierarchy
-+ [Class hierarchy](http://www.scala-lang.org/old/sites/default/files/images/classhierarchy.png)
+![Class hierarchy](https://lh3.googleusercontent.com/Hz5G9eaSlV4yrkxsDZWNNsRpDmarjSQjBUTw7ODeqegy4u03pVYJ36EXOleYEt6t5plCsxxwZ8dCDdNtNBOJJemXnOnRlNDQm-ytc3kxIuEtYU04RE74OhlCMFwDkCM9DEL2efmTbUVg9bW0Ban8dLfOy0Nl2fxeFDtEfE8tezFffz-SnW8NL0ghyq-CqJC-1YIxizaiLoocQdlzfGAgDkTtaOG2Obd_F3wIp5XSjhaN8X6U7Qf7MfYqRF7WRX2MFksFl2Go3Ne-JWzUDUD0h3yy8grua66P6NHERjm2iBk3m7pCwxtehdwELJ8iliHr7C8P8rZ4Uz8AuRwC57GmiOY36MfckDSgvjJVY38J8oVl4WUiRaQEI-HvT9p0Soqq33xc4zAZ5M8F1G8nnVufJwbaY9l7fSOM5f3P5XVb6UbzhaZqno5yZjYm44j6scIzII3txaIYB7fVX4Uu7wakPXEOj_M4IWHK6hvuiZ95aVHqCY339JbIHx8sfyvQ63-9FfVgA35MI1gbpdhSbPHcw7RCeU6tnB1TH3Dnog7MGXH8p_Om95lItqDV-Ah5uZAnW8gNmO29FH4ljDwJOSEKL4o3GBBS_zO4fTWMKCOh_DfDfAy3FahovYKTRYpEpYpDyEt8Nt8iLXZFpvAB3EWerFv6ICMiuRlnbO7N3TpwBhNjCcNyBm9JGw=w1347-h782-no)
 + `Scala.Any` is at the top of scala class hierarchy and is the base type of all scala types. It is also the base type that defines universal methods like `toString`, `equals`, `hashCode`, `==`, `!=`, etc
 + `Scala.AnyVal` is a subclass of `Scala.Any` and is the base class of all primitive types like `Byte`, `Int`, `Double`, etc
 + `Scala.AnyRef` is a base type of all reference types. Alias of `java.lang.Object`. `scala.Iterable`, `scala.Seq`, `scala.List` are base classes of `scala.AnyRef` but they also implement the trait `Scala.ScalaObject`