> paddleball vel = walls `over` paddle `over` pball vel

> walls = let upper = paint blue (translate ( 0,1.7) (rec 4.4 0.05))
>ΚΚΚΚΚΚΚΚΚΚΚΚ leftΚ = paint blue (translate (-2.2,0) (rec 0.05 3.4))
>ΚΚΚΚΚΚΚΚΚΚΚΚ right = paint blue (translate ( 2.2,0) (rec 0.05 3.4))
>ΚΚΚΚΚΚΚΚ in upper `over` left `over` right

> paddle = paint red (translate (fst mouse, -1.7) (rec 0.5 0.05))

> pball vel =
>ΚΚ let xvelΚΚΚ = vel `stepAccum` xbounce ->> negate
>ΚΚΚΚΚΚ xposΚΚΚ = integral xvel
>ΚΚΚΚΚΚ xbounce = when (xpos >* 2 ||* xpos <* -2)
>ΚΚΚΚΚΚ yvelΚΚΚ = vel `stepAccum` ybounce ->> negate
>ΚΚΚΚΚΚ yposΚΚΚ = integral yvel
>ΚΚΚΚΚΚ ybounce = when (ypos >* 1.5Κ
>ΚΚΚΚΚΚΚΚΚΚΚΚΚΚΚΚΚΚ ||* ypos `between` (-2.0,-1.5) &&*
>ΚΚΚΚΚΚΚΚΚΚΚΚΚΚΚΚΚΚΚΚΚΚ fst mouse `between` (xpos-0.25,xpos+0.25))
>ΚΚ in paint yellow (translate (xpos, ypos) (ell 0.2 0.2))

> x `between` (a,b) = x >* a &&* x <* b