var RADIUS = Math.floor((Math.random() * 40) + 1));
var MAX = Math.floor((Math.random() * 360) + 1));
var ANGLE = MAX * Math.PI / 180;

for (var i = 0; i < MAX; ++i)
{
    var newX = i + RADIUS * Math.cos(ANGLE);
    var newY = i + RADIUS * Math.sin(ANGLE);
    sprite.x = newX;
    sprite.y = newY;
}