docs: public ReadOnlyDoubleProperty lengthProperty() {
  		if (this.lengthProperty == null) {
  			this.lengthProperty = new ReadOnlyDoubleWrapper(this, MathFXAttributeNames.LENGTH);
  			this.lengthProperty.bind(Bindings.createDoubleBinding(() ->
  					Math.sqrt(lengthSquaredProperty().doubleValue()), lengthSquaredProperty()));
  		}
  		return this.lengthProperty.getReadOnlyProperty();
  	}