What do you think about adding glass blocks. They would be almost completely transparent. They would be based on the same shapes. They would have the advantage of being almost untouchable by lasers or their damage would be 10% of the possible for laser hits and on a layer of several blocks the laser would lose power, for example it would lose 30% on a thickness of three blocks. In addition they would give the possibility of using beautiful graphic effects when light would be split and refracted. Although, maybe that would be harder to do, I don't know.