<!-- NEW6 — TEST 6 · THE FIVE SHORES · part 38 -->
) {

		xAxis.setFromMatrix3Column( this, 0 );
		yAxis.setFromMatrix3Column( this, 1 );
		zAxis.setFromMatrix3Column( this, 2 );

		return this;

	}

	/**
	 * Set this matrix to the upper 3x3 matrix of the given 4x4 matrix.
	 *
	 * @param {Matrix4} m - The 4x4 matrix.
	 * @return {Matrix3} A reference to this matrix.
	 */
	setFromMatrix4( m ) {

		const me = m.elements;

		this.set(

			me[ 0 ], me[ 4 ], me[ 8 ],
			me[ 1 ], me[ 5 ], me[ 9 ],
			me[ 2 ], me[ 6 ], me[ 10 ]

		);

		return this;

	}

	/**
	 * Post-multiplies this matrix by the given 3x3 matrix.
	 *
	 * @param {Matrix3} m - The matrix to multiply with.
	 * @return {Matrix3} A reference to this matrix.
	 */
	multiply( m ) {

		return this.multiplyMatrices( this, m );

	}

	/**
	 * Pre-multiplies this matrix by the given 3x3 matrix.
	 *
	 * @param {Matrix3} m - The matrix to multiply with.
	 * @return {Matrix3} A reference to this matrix.
	 */
	premultiply( m ) {

		return this.multiplyMatrices( m, this );

	}

	/**
	 * Multiples the given 3x3 matrices and stores the result
	 * in this matrix.
	 *
	 * @param {Matrix3} a - The first matrix.
	 * @param {Matrix3} b - The second matrix.
	 * @return {Matrix3} A reference to this matrix.
	 */
	multiplyMatrices( a, b ) {

		const ae = a.elements;
		const be = b.elements;
		const te = this.elements;

		const a11 = ae[ 0 ], a12 = ae[ 3 ], a13 = ae[ 6 ];
		const a21 = ae[ 1 ], a22 = ae[ 4 ], a23 = ae[ 7 ];
		const a31 = ae[ 2 ], a32 = ae[ 5 ], a33 = ae[ 8 ];

		const b11 = be[ 0 ], b12 = be[ 3 ], b13 = be[ 6 ];
		const b21 = be[ 1 ], b22 = be[ 4 ], b23 = be[ 7 ];
		const b31 = be[ 2 ], b32 = be[ 5 ], b33 = be[ 8 ];

		te[ 0 ] = a11 * b11 + a12 * b21 + a13 * b31;
		te[ 3 ] = a11 * b12 + a12 * b22 + a13 * b32;
		te[ 6 ] = a11 * b13 + a12 * b23 + a13 * b33;

		te[ 1 ] = a21 * b11 + a22 * b21 + a23 * b31;
		te[ 4 ] = a21 * b12 + a22 * b22 + a23 * b32;
		te[ 7 ] = a21 * b13 + a22 * b23 + a23 * b33;

		te[ 2 ] = a31 * b11 + a32 * b21 + a33 * b31;
		te[ 5 ] = a31 * b12 + a32 * b22 + a33 * b32;
		te[ 8 ] = a31 * b13 + a32 * b23 + a33 * b33;

		return this;

	}

	/**
	 * Multiplies every component of the matrix by the given scalar.
	 *
	 * @param {number} s - The scalar.
	 * @return {Matrix3} A reference to this matrix.
	 */
	multiplyScalar( s ) {

		const te = this.elements;

		te[ 0 ] *= s; te[ 3 ] *= s; te[ 6 ] *= s;
		te[ 1 ] *= s; te[ 4 ] *= s; te[ 7 ] *= s;
		te[ 2 ] *= s; te[ 5 ] *= s; te[ 8 ] *= s;

		return this;

	}

	/**
	 * Computes and returns the determinant of this matrix.
	 *
	 * @return {number} The determinant.
	 */
	determinant() {

		const te = this.elements;

		const a = te[ 0 ], b = te[ 1 ], c = te[ 2 ],
			d = te[ 3 ], e = te[ 4 ], f = te[ 5 ],
			g = te[ 6 ], h = te[ 7 ], i = te[ 8 ];

		return a * e * i - a * f * h - b * d * i + b * f * g + c * d * h - c * e * g;

	}

	/**
	 * Inverts this matrix, using the [analytic method](https://en.wikipedia.org/wiki/Invertible_matrix#Analytic_solution).
	 * You can not invert with a determinant of zero. If you attempt this, the method produces
	 * a zero matrix instead.
	 *
	 * @return {Matrix3} A reference to this matrix.
	 */
	invert() {

		const te = this.elements,

			n11 = te[ 0 ], n21 = te[ 1 ], n31 = te[ 2 ],
			n12 = te[ 3 ], n22 = te[ 4 ], n32 = te[ 5 ],
			n13 = te[ 6 ], n23 = te[ 7 ], n33 = te[ 8 ],

			t11 = n33 * n22 - n32 * n23,
			t12 = n32 * n13 - n33 * n12,
			t13 = n23 * n12 - n22 * n13,

			det = n11 * t11 + n21 * t12 + n31 * t13;

		if ( det === 0 ) return this.set( 0, 0, 0, 0, 0, 0, 0, 0, 0 );

		const detInv = 1 / det;

		te[ 0 ] = t11 * detInv;
		te[ 1 ] = ( n31 * n23 - n33 * n21 ) * detInv;
		te[ 2 ] = ( n32 * n21 - n31 * n22 ) * detInv;

		te[ 3 ] = t12 * detInv;
		te[ 4 ] = ( n33 * n11 - n31 * n13 ) * detInv;
		te[ 5 ] = ( n31 * n12 - n32 * n11 ) * detInv;

		te[ 6 ] = t13 * detInv;
		te[ 7 ] = ( n21 * n13 - n23 * n11 ) * detInv;
		te[ 8 ] = ( n22 * n11 - n21 * n12 ) * detInv;

		return this;

	}

	/**
	 * Transposes this matrix in place.
	 *
	 * @return {Matrix3} A reference to this matrix.
	 */
	transpose() {

		let tmp;
		const m = this.elements;

		tmp = m[ 1 ]; m[ 1 ] = m[ 3 ]; m[ 3 ] = tmp;
		tmp = m[ 2 ]; m[ 2 ] = m[ 6 ]; m[ 6 ] = tmp;
		tmp = m[ 5 ]; m[ 5 ] = m[ 7 ]; m[ 7 ] = tmp;

		return this;

	}

	/**
	 * Computes the normal matrix which is the inverse transpose of the upper
	 * left 3x3 portion of the given 4x4 matrix.
	 *
	 * @param {Matrix4} matrix4 - The 4x4 matrix.
	 * @return {Matrix3} A reference to this matrix.
	 */
	getNormalMatrix( matrix4 ) {

		return this.setFromMatrix4( matrix4 ).invert().transpose();

	}

	/**
	 * Transposes this matrix into the supplied array, and returns itself unchanged.
	 *
	 * @param {Array<number>} r - An array to store the transposed matrix elements.
	 * @return {Matrix3} A reference to this matrix.
	 */
	transposeIntoArray( r ) {

		const m = this.elements;

		r[ 0 ] = m[ 0 ];
		r[ 1 ] = m[ 3 ];
		r[ 2 ] = m[ 6 ];
		r[ 3