Background extends THREE.Mesh (an Object3D) and is used to render a background panel for a Three node.
Unlike the DOM's background, this Background is designed to float a few centimeters behind the node's BorderLine.
function Background(width = 0, height = 0, radius = [0, 0, 0, 0]) {
	THREE.Mesh.call(
		this,
		new BackgroundGeometry(width, height, radius),
		new THREE.MeshStandardMaterial({
			side: THREE.DoubleSide
		}),
		undefined
	)
	this.name = 'Background'
	// Shadow SOM nodes are ignored during some layout calculations
	this.shadowSOM = true
}