StarMorph

- XLogo animation

A random pulsating and rotating star form drawn in overlaid red and green.

To New
  # set default screen, pen and turtle values
  ResetAll SetScreenSize [400 400] HideTurtle
  SetSC Black SetPC Green SetPS 1 PenUp
End

To Init :Theta
  Make "R 400*Sin (2*:Theta)
  Make "A :R*Sin :Theta
  Make "B :R*Cos :Theta
  Make "X 0 Make "Y 0
End

To StarMorph
  Make "Col1 Absolute (:Col1-3)
  Make "Col2 Absolute (:Col2-3)
  For [Theta 0 90 0.5] [
    Init :Theta
    SetH 0 PenUp Right :Theta
    Repeat 9 [
      Forward :A Left 140
      Forward :B Left 140
      Make "X :X + :X
      Make "Y :Y + :Y]
    SetXY Minus :X/9 Minus :Y/9
    SetH 0 PenDown Right :Theta
    Repeat 9 [
      SetPC :Col1 Forward :A Left 140
      SetPC :Col2 Forward :B Left 140]
    Refresh Wait 2 Wash]
End

To Go
  New Animation SetPW 2
  Make "Col1 1 Make "Col2 2
  Forever [StarMorph]
End

StarMorph
StarMorph

Procedures blue
Variables pink
Comments green
Library gray