Example -- class

 
  Behavior subclass: #Ctr
  instanceVariableNames: 'value'
  Ctr methodsFor: 'initialization'
     initialize
  	value := 0.
  Ctr methodsFor: 'modifications'
     add: aValue
  	value := value + aValue.
  Ctr methodsFor: 'inspection'
     value
  	^value
slide: Smalltalk -- objects (2)