code: function(a,b) {
  			if( hasXY( a ) && hasXY( b ) ){
  				this.x = mathUtils.clip(this.x, a.x, b.x);
  				this.y = mathUtils.clip(this.y, a.y, b.y);
  			} else if( isRect( a ) ){
  				this.x = mathUtils.clip(this.x, a.x, a.x + a.width);
  				this.y = mathUtils.clip(this.y, a.y, a.y + a.height);
  			}
  			return this;
  		}
docs: Forcefully fits the vector in the given rectangle.
  
  @param a
  either a Rectangle by itself or the Vec2D min
  @param b
  Vec2D max
  @return itself