redef var normals is lazy do
		var normals = new Array[Float]
		var faces_normals = [
			[0.0, 0.0, -1.0],
			[0.0, 0.0,  1.0],
			[ 1.0, 0.0, 0.0],
			[-1.0, 0.0, 0.0],
			[0.0, -1.0, 0.0],
			[0.0,  1.0, 0.0]]
		for f in faces_normals do for i in 6.times do normals.add_all f
		return normals
	end