draw_circle

#
# Draws an unfilled circle, thanks shawn24!
#
CIRCLE_STEP = 10
def draw_circle(cx,cy,r,color)      
  0.step(360, CIRCLE_STEP) do |a1|
  a2 = a1 + CIRCLE_STEP
  $window.draw_line cx + Gosu.offset_x(a1, r), cy + Gosu.offset_y(a1, r), color, cx + Gosu.offset_x(a2, r), cy + Gosu.offset_y(a2, r), color, 9999
 end
end

you thief!!
https://github.com/shawn42/gamebox/blob/master/lib/gamebox/wrapped_screen.rb
It's all open-source my friend...

:D

... right, still giving you credit everywhere I can for that snippet :)