LOGO-L> 3-D color effects

[JENEVOLD@aol.com]

Julie Clune submitted Simple Flower:

repeat 11 [for [i 0 359] [fd 1 rt (sin :i / 2)]]

which almost, but not exactly, returns to
its starting position. This fact was exploited by
Craig Denson and George Mills to produce
3-D color effects.

to flower3d
cs ht clearpalette
repeat 16 [
   setpencolor (list repcount*256/16 0 0)
   repeat 11 [for [i 0 359] [fd 1 rt (sin :i / 2)]]
]
end

(This works in MSW Logo.)

You can get similar 3-D effects with many patterns
which do return exactly to their starting positions.
Simply insert a small offset or angle for each repeat.

For example, take this Dahlia variation by David Eisenstat:

repeat 8 [rt 45 repeat 4 [repeat 90 [fd 2 rt 2] rt 90]]

to dahlia3d
cs ht clearpalette
repeat 16 [
   setpencolor (list repcount*256/16 0 0)
   repeat 8 [rt 45 repeat 4 [repeat 90 [fd 2 rt 2] rt 90]]
   rt .4
]
end

- Keith Enevoldsen


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