Have you ever implemented a programming language?

(level (nova 270))

(enemy nova (angle) (speed a i)
  (set a 0)
  (while 1
    (if (<= 15 a)
      (begin (set a (- a 15))
             (wait 0.2)))
    (wait 0.04)
    # i iterates over the circle to fire a nova
    (set i 0)
    (while (< i 360)
      (fire wavy (+ angle (+ a i)) 70)
      (set i (+ 15 i)))
    (set a (+ 0.5 a))))

# zig-zag around the given angle
(bullet wavy (angle speed) (orig-angle offset)
  (set orig-angle angle)
  (set offset 30)
  (while 1
    (set angle (+ orig-angle offset))
    (set offset (* offset (- 0 1)))
    (wait 0.25)))

functions
   fib(x)
      if x==0 then 0 else
         if x==1 then 1 else
            call fib(x-1) + call fib(x-2)
         end
      end
   end
in
   call fib(12)
end

if ("4" + "2") as number > 30 then "seems to be working"
                              else "oh dear"