A flat crystal is not modest at all. Under the right illumination, its internal order acts like an optical circuit board, steering photons so aggressively that the surface sketch of lines and facets starts to look like a portal cut into space.
What seems like magic is wave accounting. Each tiny step, crack or lattice plane forces light to obey interference, where peaks and troughs add or cancel, and refraction, where phase velocity shifts as the wave enters regions with different refractive index. Those repeated nudges build a full photonic band structure, the optical analogue of an electron band diagram in solid-state physics, so certain directions and colors are forced to bend, stall, or vanish.
The bolder claim is that this flat geometry only looks flat. When crystal layers, defects or moire-like overlays impose periodicity in one direction and quasi-periodicity in another, the math of Maxwell’s equations can be rewritten as if light were moving in a higher-dimensional lattice. Topological edge modes, born from that abstract space, then creep along cracks and boundaries, hugging a line or corner while the bulk stays dark. To the eye, those protected channels read as glowing cuts and impossible bends, as if the drawing on the surface had been extruded into a hidden axis and lit from within.
