Overlapping Curved Dynamic Mask prob

programming flash
1

hey, im trying to make a script that randomly makes slashes revealing a picture underneath as if it was being painted or something. It sorta works, but the overlapping shapes inverse each other. I tried putting them in individual movie clips within the mask clip, but no luck. Thanks in advance.
(I have a picture clip called “pic” on the stage")

/////////////initialize//////////////
onClipEvent(load){

_root.createEmptyMovieClip(“mask”, 0);
_root.pic.setMask(_root.mask);

}
///////////////main///events//////

onClipEvent(enterFrame){
with(_root.mask){
lineStyle( 1, 0x0000FF, 100 ); //Why dont lines work as dynamic masks? only filled shapes?
beginFill(0x0000FF,100);

///////////Create Random Curve locations////////

x1=(random((_root.pic._width2))(_root.pic._width));
x2=(random((_root.pic._width2))-(_root.pic._width));
y1=(random((_root.pic._height2))-(_root.pic._height));
y2=(random((_root.pic._height2))-(_root.pic._height));

///////////////////find starting point///////////////

xx=((_root.pic._width/2)+(random(60)-30));
yy=((_root.pic._height/2)+(random(60)-30));

///////////////////////draw it///////////////////////

moveTo(xx,yy);
curveTo(x1,y1,x2,y2);
curveTo((x1+random(150)),(y1+random(150)),xx,yy);
endFill();

}
}