add( object ) {
		/* eslint-enable no-unused-vars */

		/**
		 *
		 * @type {Array.<Object3D>}
		 */
		const validChildren = [];

		for ( let i = 0; i < arguments.length; i++ ) {

			const argument = arguments[ i ];

			if ( !argument.isUI || argument.isBox ) {

				validChildren.push( argument );

			} else {

				console.warn( 'Block element can only contain Box elements.', argument );

			}

		}

		return super.add( ...validChildren );

	}
A Block Element can only contains box elements
@override
@param {...Object3D} object
@return {this}