lengthSq() {

		return this.x * this.x + this.y * this.y;

	}
Computes the square of the Euclidean length (straight-line length) from
(0, 0) to (x, y). If you are comparing the lengths of vectors, you should
compare the length squared instead as it is slightly more efficient to calculate.

@return {number} The square length of this vector.