- polar plots

All these spirals are drawn using polar co-ordinates. See Spirals for spirals drawn using calculation of curvature.
This draws a ten turn Archimedes spiral.

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

To P2R :Radius :Angle
  Make "X :Radius * Cos :Angle
  Make "Y :Radius * Sin :Angle
  Output List :X :Y

To Spiral :Angle
  # Archimides Spiral
  Make "Radius :Angle/20

To Go
  New SetPC Yellow
  For [Angle 0 3600] [
    Spiral :Angle
    SetPos P2R :Radius :Angle PenDown]

For Fermats spiral, Radius is proportional to the square root of the Angle. Copy and paste to update the spiral procedure.

To Spiral :Angle
  # Fermats Spiral
  Make "Radius 3*Power :Angle 0.5

An equiangular spiral grows very quickly.

To Spiral :Angle
  # Equiangular Spiral
  Make "Radius Power 1.002 :Angle

This adds a small ripple to an Archimedes spiral, giving an illusion of petals. You will need to increase the number of steps to 8860.

To Spiral :Angle
  # Archimides Daisy
  Make "Offset Sin 7.05*:Angle
  Make "Radius :Angle/52 + (Power (:Angle/2000) 2) * :Offset
  SetPC ( List 0 (Round 127.5 * (1+:Offset)) 255 )

Archemedes Spiral
Arch Spiral


Archemedes Spiral 2
Arch Spiral2

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