code: public DoubleProperty lengthSquaredProperty() {
  		if (this.lengthSquareProperty == null) {
  			this.lengthSquareProperty = new ReadOnlyDoubleWrapper(this, MathFXAttributeNames.LENGTH_SQUARED);
  			this.lengthSquareProperty.bind(Bindings.createDoubleBinding(() -> {
  				return Vector2ifx.this.x.doubleValue() * Vector2ifx.this.x.doubleValue()
  						+ Vector2ifx.this.y.doubleValue() * Vector2ifx.this.y.doubleValue();
  			}, this.x, this.y));
  		}
  		return this.lengthSquareProperty;
  	}
docs: Replies the property that represents the length of the vector.
  
  @return the length property