arcs

function onGLC(glc) {
    glc.loop();
    // glc.playOnce();
    glc.size(540, 540);
    glc.setDuration(2.5);
    glc.setFPS(40);
    glc.setMode("single");
    // glc.setEasing(false);

    var list = glc.renderList,
        width = glc.w,
        height = glc.h,
        color = glc.color,
        ox = width/2,
        oy = height/2,
        TWO_PI = Math.PI*2;

    // your code goes here:

    var num = 20;

    for (var i=0; i<num; i++) {
        var rad = 25+i*10
            offSet = Math.random()*360,
            end = 45+Math.random()*90;
        list.addCircle({
            x:ox,
            y:oy,
            radius: rad,
            lineWidth:25,
            rotation: i%2===0?[offSet,offSet+360]:[offSet,offSet-360],
            startAngle: 0,
            endAngle: end,
            strokeStyle: i%3===0?"white":"black",
            fill: false,
            stroke: true,
            phase: i/num,
            lineCap: "square"
        });
    }
}