/**
	 * Fences of the voxel. @see FenceType
	 * - bit  0.. 3: Fence type of the NE edge.
	 * - bit  4.. 7: Fence type of the SE edge.
	 * - bit  8..11: Fence type of the SW edge.
	 * - bit 12..15: Fence type of the NW edge.
	 */
	uint16 fences;