make "angle 45
make "radius 20
to quarter
penup
back (:radius * sin :angle) left :angle
pendown
arc (:angle * 2) :radius
penup
right :angle
forward (:radius * sin :angle)
pendown
end
to rquarter
make "deg pick [[0 6] [90 4] [180 1] [270 0]]
left first :deg
setpencolor last :deg
quarter
setpencolor 0
right first :deg
end
to grid
repeat 8 [
repeat 8 [
rquarter
penup
forward (sin :angle) * :radius * 2
pendown
]
penup
back (sin :angle) * :radius * 2 * 8
right 90
forward (sin :angle) * :radius * 2
left 90
pendown
]
end
clearscreen
window
setbg 7
setpensize 3
grid
