by Rayme T
This tessellation shows translation symmetry (a.k.a. "slide" and/or "glide" symmetry).
The "tile" (tile = repeating shape) is very neatly, precisely reproduced and fits with all the other tiles perfectly, without gaps or overlaps. That's what a proper tessellation does.
However, only one side out of four resembles the theme, "faces". That's why this tile shape creates a valid abstract tessellation, but when we make the theme "faces", it is not an Escher-style tessellation.