"Lecture 20, CSE341, Spring 2004"
"Subclassing, Late-Binding, and Class Methods in Smalltalk"

pt distFromOrigin2

pt x:6 y:8.
pt distFromOrigin

pt x:6; y:8.
pt distFromOrigin

"after adding ColorPoint..."
cpt := MyColorPoint new x: 4 y: 3.
cpt color

ppt := MyPolarPoint new.
ppt r:2 theta:0.
ppt x

ppt x:4; y:3.
ppt distFromOrigin2 + ppt distFromOrigin2 

tdp := My3DPoint new.
tdp x:1; y:1; z:1.
(tdp sup) scaleBy: 2

My3DColorPoint newAtOrigin