jitters

function onGLC(glc) {
    glc.loop();
    // glc.playOnce();
    glc.size(540, 540);
    glc.setDuration(3);
    glc.setFPS(30);
    glc.styles.backgroundColor = "#202020";
    // glc.setMode("single");
    // glc.setEasing(false);

    var list = glc.renderList,
        width = glc.w,
        height = glc.h,
        color = glc.color;

    // your code goes here:

    var gradient = color.createLinearGradient(0, -height/2, 0, height/2);
    gradient.addColorStop(1, "#232526");
    gradient.addColorStop(0, "#414345");

    /*
    list.addRect({
        x:width/2,
        y:height/2,
        w:width,
        h:height,
        fillStyle: gradient
    });
    */

    var num = 50;
    for (var i=0; i<num; i++) {
       // if (Math.random(1)>.3) {
        list.addOval({
            x: width/2,
            y: [height*.3, height*.7],
            rx: 20+i*3,
            ry: (20+i*3)/2,
            lineWidth: 1,
            strokeStyle: "rgba(255,255,255,.5)",
            fill: false,
            stroke: true,
            rotation: [0,180],
            startAngle: [0,180],
            endAngle: [180,360],
            lineWidth: 1,
            shake: 5,
            phase: .25/num*i
        });
        //}
    }
}