Using the data storage type defined on this page for raster images, and the draw_line function defined in this one, draw a quadratic bezier curve
(definition on Wikipedia).

// Daw a Cubic bezier curve
//  #20, #30 = Start point
//  #21, #31 = Control point 1
//  #22, #32 = Control point 2
//  #23, #33 = end point
//  #40 = depth of recursion
 
:CUBIC_BEZIER:
if (#40 > 0) {
    #24 = (#20+#21)/2;              #34 = (#30+#31)/2
    #26 = (#22+#23)/2;              #36 = (#32+#33)/2
    #27 = (#20+#21*2+#22)/4;        #37 = (#30+#31*2+#32)/4
    #28 = (#21+#22*2+#23)/4;        #38 = (#31+#32*2+#33)/4
    #29 = (#20+#21*3+#22*3+#23)/8;  #39 = (#30+#31*3+#32*3+#33)/8
    Num_Push(20,40)
        #21 = #24; #31 = #34    // control 1
        #22 = #27; #32 = #37    // control 2
        #23 = #29; #33 = #39    // end point
        #40--
        Call("CUBIC_BEZIER")    // Draw "left" part
    Num_Pop(20,40)
    Num_Push(20,40)
        #20 = #29; #30 = #39    // start point
        #21 = #28; #31 = #38    // control 1
        #22 = #26; #32 = #36    // control 2
        #40--
        Call("CUBIC_BEZIER")    // Draw "right" part
    Num_Pop(20,40)
} else {
    #1=#20; #2=#30; #3=#23; #4=#33
    Call("DRAW_LINE")
}
return