#mkdrawf page 40

( $conv := $2pi / 360 )
define Spiral {
  ( ( %theta := 0  %r := %dr ) )
  For %i from 0 to ( %n - 0.5 ) {
    RLine ( %r * cos ( $conv * %theta ) )
          ( %r * sin ( $conv * %theta ) )
    ( ( %r := %r + %dr  %theta := %theta + %dt ) )
    IfLess 360 %theta
      ( %theta := %theta - 360 )
    EndIf
  }
}
Path {
  Outlinecolour r0g0b0  Width 0
  Move 250 250
  Spiral { %dr .5 %dt 65 %n 500 }
}
