CAT SHIELD by Sarah
As an abstract shape, this is a tessellation. Geometrically, it's a good tessellation: The basic shape repeats and fits together seamlessly without gaps or overlaps.
Artistically, it is not an Escher-style tessellation because the shape of the shield/wing/cape is somewhat arbitrary. Its shape doesn't clearly tell us "this is a superhero cat's cape." A good Escher-style tessellation should be recognizable as a particular animal or person or object by its silhouette alone. In Sarah's "Cat Shield", if we only saw the outline, we wouldn't know what it is until Sarah tels us that it's a shield and shows the interior details.
Emotionally, that cat looks alarmed. I'm not sure this cat is comfortable being strapped to the shield. Did Alfred the Class Pet Hamster trick that poor cat into this? Or did the cat volunteer?
This type of tessellation symmetry is called a "translation", also known as a "slide" and/or "glide" because its basic shape is reproduced by moving the copies of the basic shape along a straight line without tilting or resizing the copies. That is, there's no spinning (rotation) or reflection (mirroring, flipping) or resizing.