Visual with Morph

Exercise 6.1

Just replace all Object occurrences with PlacedMorph:

PlacedMorph subclass: #SpaceWar
   instanceVariableNames: 'centralStar ships torpedoes'
   classVariableNames: ''
   poolDictionaries: ''
   category: 'Spacewar!'

PlacedMorph subclass: #CentralStar
   instanceVariableNames: 'mass'
   classVariableNames: ''
   poolDictionaries: ''
   category: 'Spacewar!'

PlacedMorph subclass: #SpaceShip
   instanceVariableNames: 'name position heading velocity
      fuel torpedoes mass acceleration'
   classVariableNames: ''
   poolDictionaries: ''
   category: 'Spacewar!'

Exercise 6.2

Mobile subclass: #SpaceShip
   instanceVariableNames: 'name fuel torpedoes'
   classVariableNames: ''
   poolDictionaries: ''
   category: 'Spacewar!'

Mobile subclass: #Torpedo
   instanceVariableNames: 'lifeSpan'
   classVariableNames: ''
   poolDictionaries: ''
   category: 'Spacewar!'