"Smalltalk class methods" "(define class methods zero in Point and 3DPoint and zerodimThunk: in 3DPoint)" "inspecting the class hierarchy" p := My3DPoint new. p := p class. "all objects understand the class message" p := p superclass. "class objects understand superclass" p := p superclass. p := p superclass. p := p superclass. p := p superclass "nil is not a class object" "metaclass madness" p := My3DPoint new. p := p class. p := p class. p := p class. p := p class. p := p class. p := p class