#1 Geometrical

I'm playing scattered polaroids' game now! %>

This is meant to represent "geometrical". It's not quite an infinite plain, but it does have some small dots on it (0.2 millimetres) which are almost visible (if you know where to look). It also demonstrates that the slide can trap and guide light through it, that's why the edge is bright, and that's something which is tightly constrained from a geometrical perspective too.