<!-- NEW2 — TEST 2 · THE DISTRICT OF 800 · part 50 -->

			}

			this.set( x, y, z, angle );

			return this; // return 180 deg rotation

		}

		// as we have reached here there are no singularities so we can handle normally

		let s = Math.sqrt( ( m32 - m23 ) * ( m32 - m23 ) +
			( m13 - m31 ) * ( m13 - m31 ) +
			( m21 - m12 ) * ( m21 - m12 ) ); // used to normalize

		if ( Math.abs( s ) < 0.001 ) s = 1;

		// prevent divide by zero, should not happen if matrix is orthogonal and should be
		// caught by singularity test above, but I've left it in just in case

		this.x = ( m32 - m23 ) / s;
		this.y = ( m13 - m31 ) / s;
		this.z = ( m21 - m12 ) / s;
		this.w = Math.acos( ( m11 + m22 + m33 - 1 ) / 2 );

		return this;

	}

	/**
	 * Sets the vector components to the position elements of the
	 * given transformation matrix.
	 *
	 * @param {Matrix4} m - The 4x4 matrix.
	 * @return {Vector4} A reference to this vector.
	 */
	setFromMatrixPosition( m ) {

		const e = m.elements;

		this.x = e[ 12 ];
		this.y = e[ 13 ];
		this.z = e[ 14 ];
		this.w = e[ 15 ];

		return this;

	}

	/**
	 * If this vector's x, y, z or w value is greater than the given vector's x, y, z or w
	 * value, replace that value with the corresponding min value.
	 *
	 * @param {Vector4} v - The vector.
	 * @return {Vector4} A reference to this vector.
	 */
	min( v ) {

		this.x = Math.min( this.x, v.x );
		this.y = Math.min( this.y, v.y );
		this.z = Math.min( this.z, v.z );
		this.w = Math.min( this.w, v.w );

		return this;

	}

	/**
	 * If this vector's x, y, z or w value is less than the given vector's x, y, z or w
	 * value, replace that value with the corresponding max value.
	 *
	 * @param {Vector4} v - The vector.
	 * @return {Vector4} A reference to this vector.
	 */
	max( v ) {

		this.x = Math.max( this.x, v.x );
		this.y = Math.max( this.y, v.y );
		this.z = Math.max( this.z, v.z );
		this.w = Math.max( this.w, v.w );

		return this;

	}

	/**
	 * If this vector's x, y, z or w value is greater than the max vector's x, y, z or w
	 * value, it is replaced by the corresponding value.
	 * If this vector's x, y, z or w value is less than the min vector's x, y, z or w value,
	 * it is replaced by the corresponding value.
	 *
	 * @param {Vector4} min - The minimum x, y and z values.
	 * @param {Vector4} max - The maximum x, y and z values in the desired range.
	 * @return {Vector4} A reference to this vector.
	 */
	clamp( min, max ) {

		// assumes min < max, componentwise

		this.x = clamp( this.x, min.x, max.x );
		this.y = clamp( this.y, min.y, max.y );
		this.z = clamp( this.z, min.z, max.z );
		this.w = clamp( this.w, min.w, max.w );

		return this;

	}

	/**
	 * If this vector's x, y, z or w values are greater than the max value, they are
	 * replaced by the max value.
	 * If this vector's x, y, z or w values are less than the min value, they are
	 * replaced by the min value.
	 *
	 * @param {number} minVal - The minimum value the components will be clamped to.
	 * @param {number} maxVal - The maximum value the components will be clamped to.
	 * @return {Vector4} A reference to this vector.
	 */
	clampScalar( minVal, maxVal ) {

		this.x = clamp( this.x, minVal, maxVal );
		this.y = clamp( this.y, minVal, maxVal );
		this.z = clamp( this.z, minVal, maxVal );
		this.w = clamp( this.w, minVal, maxVal );

		return this;

	}

	/**
	 * If this vector's length is greater than the max value, it is replaced by
	 * the max value.
	 * If this vector's length is less than the min value, it is replaced by the
	 * min value.
	 *
	 * @param {number} min - The minimum value the vector length will be clamped to.
	 * @param {number} max - The maximum value the vector length will be clamped to.
	 * @return {Vector4} A reference to this vector.
	 */
	clampLength( min, max ) {

		const length = this.length();

		return this.divideScalar( length || 1 ).multiplyScalar( clamp( length, min, max ) );

	}

	/**
	 * The components of this vector are rounded down to the nearest integer value.
	 *
	 * @return {Vector4} A reference to this vector.
	 */
	floor() {

		this.x = Math.floor( this.x );
		this.y = Math.floor( this.y );
		this.z = Math.floor( this.z );
		this.w = Math.floor( this.w );

		return this;

	}

	/**
	 * The components of this vector are rounded up to the nearest integer value.
	 *
	 * @return {Vector4} A reference to this vector.
	 */
	ceil() {

		this.x = Math.ceil( this.x );
		this.y = Math.ceil( this.y );
		this.z = Math.ceil( this.z );
		this.w = Math.ceil( this.w );

		return this;

	}

	/**
	 * The components of this vector are rounded to the nearest integer value
	 *
	 * @return {Vector4} A reference to this vector.
	 */
	round() {

		this.x = Math.round( this.x );
		this.y = Math.round( this.y );
		this.z = Math.round( this.z );
		this.w = Math.round( this.w );

		return this;

	}

	/**
	 * The components of this vector are rounded towards zero (up if negative,
	 * down if positive) to an integer value.
	 *
	 * @return {Vector4}