1> (define cp (new-instance color-point 5 6 'red))

2> (send 'get-color cp)
red

3> (send 'getx cp)
5

4> (send 'gety cp)
6

5> (define cp-1 (send 'add cp (new-instance color-point 1 2 'green))) 

6> (send 'getx cp-1)
6

7> (send 'gety cp-1)
8

8> (send 'get-color cp-1)
Undefined message get-color

9> (send 'type-of cp-1)
point