function(o, angle) {
            angle = (angle + 360) % 360;
            this.toPolar(o);
            this.y += toRad(angle);
            var p = point.fromPolar(this.x, this.y, o);
            this.x = p.x;
            this.y = p.y;
            return this;
        }
function(o, angle) {
            angle = (angle + 360) % 360;
            this.toPolar(o);
            this.y += toRad(angle);
            var p = point.fromPolar(this.x, this.y, o);
            this.x = p.x;
            this.y = p.y;
            return this;
        }
function ( o , angle ) { angle = ( angle + 360 ) % 360 ; this . toPolar ( o ) ; this . y += toRad ( angle ) ; var p = point . fromPolar ( this . x , this . y , o ) ; this . x = p . x ; this . y = p . y ; return this ; }
Rotate point by angle around origin o.
Rotate point by angle around origin o .