(
    ; mouse over the image to draw circles
    (sc-init 800 600)
    (sc-opt SCREEN_AUTO_BLIT 0)

    (:loop)
        (sc-poll)
        (sc-mouse r4 r5 (ov? (j :loop)))
        (itf r4)
        (itf r5)

        (ld r0 0.0)
        (def RADIUS 50.0)
        (:circle)
            (fsin r1 r0)
            (fcos r2 r0)

            (fmul r1 RADIUS)
            (fmul r2 RADIUS)

            (fadd r1 r4)
            (fadd r2 r5)

            (fti r1)
            (fti r2)
            (sc-px r1 r2 #66ff00)
            (fadd r0 0.1) ; make lower for a smoother circle
            (fcmp r0 TAU
                (ge?
                    (sc-blit)
                    (j :loop)))
        (j :circle)
    (j :loop)
)