- illusory shape
Named after Professor Gaetano Kanizsa of the University of Trieste who first introduced them. The triangle appears to float above the background. Orders of 4 or 5 can also be tried.
To New
# set default screen, pen and turtle values
ResetAll SetScreenSize [400 400] HideTurtle
SetSC Black SetPC Green SetPS 1 PenUp
End
To Dart
# Draw dart shape, TP
Right :Angle/2 PenDown Back :Size PenUp Forward :Size
Left :Angle PenDown Back :Size PenUp Forward :Size Right :Angle/2
End
To Arch :Angle :Radius
# symmetrical arc drawn relative to turtle heading
Arc :Radius Heading-:Angle/2
Heading+:Angle/2
End
To Go :Order
New SetPW 2
Make "Angle 180-(360/:Order)
Repeat :Order [
Forward 140 Dart :Angle 30 Arch 360-:Angle 30
Forward 10 Fill Back 10
SetPC Black Dart :Angle 30 SetPC Green
Back 140 Left 180/:Order
Forward 140 Dart :Angle Item :Order [0 0 78 56 44
32]
Back 140 Left 180/:Order]
End
Try Go 4 and Go 5 too.
Kanisza Square
Kanisza Pent
Procedures blue
Variables pink
Comments green
Library gray
Visit XLogo
web site