Sunflower

- XLogo

Entwined left and right logarithmic spirals can be seen in the seed arrangemnets of many flowers, especially the Sunflower.
In DrawSeed, comment in to fill seeds with color, or draw as thin lines instead.

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

To DrawSeed
  Left 45 PenDown Repeat 4 [Back 7 Right 90] PenUp
  # Right 45 Back 5 Fill     # fill with yellow
  # PenDown Forward 16 PenUp     # thin lines
End

To Go
  New SetPC Yellow
  For [Angle 200 90000 222.5] [     # 222.5=360/1.618 Also try 445
  Make "Radius 0.6 * Power :Angle 0.5
  Home SetH :Angle Forward :Radius
  DrawSeed]
End

Sunflower
Sunflower

Book Info
MathOGraphics
Pages 135-142


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