onFrame(playAnimate);
        }

        function calculatePositon(dot1, dot2, len) {
            var points = [];

            var x, y;
            var EPS = len;
            var scale = 1;
            dot1[0] *= scale;
            dot1[1] *= scale;
            len *= scale;
            var k = (dot1[0] - dot2[0]) / (dot1[1] - dot2[1]);
            var y1, y2, y3;

            var dis = Math.sqrt(
                (dot1[0] - dot2[0]) * (dot1[0] - dot2[0]) +
                (dot1[1] - dot2[1]) * (dot1[1] - 