- XLogo recursion
A square drawn many times. Each time, slightly smaller, with a 4 degree rotation and color change. The corners of the squares appear prominent as a spiral.
To New
# set default screen, pen and turtle values
ResetAll SetScreenSize [400 400] HideTurtle
SetSC Black SetPC Green SetPS 1 PenUp
End
To SpinSquare :Side
If :Side < 12 [Stop]
SetPC Hue 1.4*:Side
Square :Side
Left 4
SpinSquare :Side-8
End
To Hue :Theta
# Output RGB hue list from angle :Theta
Make "Red Round 127.5*(1+Sin :Theta)
Make "Green Round 127.5*(1+Sin (:Theta+120))
Make "Blue Round 127.5*(1+Sin (:Theta+240))
Output (List :Red :Green :Blue)
End
To Square :Side
# square (side x side) drawn from centre (tp)
Back :Side/2 Right 90 Back :Side/2 PenDown
Repeat 4 [
Forward :Side Left 90]
PenUp Forward :Side/2 Left 90 Forward :Side/2 # r2c
End
To Go
New Right 6 SpinSquare 340
End