View.Set ("graphics:max,max")
proc ripples (mx, my : int)
    for i : 1 .. 15
        drawoval (mx, my, 10 * i, 10 * i, blue)
    end for
end ripples
var mx, my, mb : int
loop
    mousewhere (mx, my, mb)
    if mb = 1 then
        ripples (mx, my)
    end if
end loop