I understand the non-repeating patterns. I just don't see how a regular 3D lattice can produce such a pattern. Unless the light source creating this shadow is a

I understand the non-repeating patterns. I just don't see how a regular 3D lattice can produce such a pattern. Unless the light source creating this shadow is a point-source rather than a parallel one? I guess I'm just looking for confirmation on this thought: A parallel light shone through a repeating 3D lattice will always produce a repeating 2D lattice.