ANGELS by Anea
This is a well-done classic translational (slide) tessellation. You can tell it's a translational tessellation because the angels are all at the same angle-- they're simply displaced along the X axis and Y axis, without rotating to a new angle.
Here's an artistic point to consider: Anea needn't have made the black lines between angels wider in some places and narrower in others. Ideally, a tessellation's "tiles" (the "tiles" are angel shapes, in this case) fit together smoothly with uniformly wide lines between the tiles. This is what we mean when we say that a tessellation's tiles should fit together without gaps: a separating line that's wide-ish at one point looks like it's a gap.