Black work that utilizes the rules of geometry and basic dot work is a slippery slope. You have to understand planes and shapes, and make direct decisions with your line or dot that will influence the whole feel of a piece. So, when an artist can really knock some basic-yet-detailed, simple-yet-complex geometrics and dot work, and capture form and function at the same time, it's fucking fantastic.
Mark Ostein, based in Lisbon, Portugal, manages to give us something to look at from every possible angle. His animals break out of lines, or fold back into geometry; they lunge out at us, or entice us to come closer.
Ostein's animals are also relatively tiny. Dot work tends to be itty-bitty, but Ostein packs a ton of detail into a small space. His animals have a texture and weight to them, while also maintaining a clarity that a small tattoo can sometimes lose.
Check Ostein's whole deal out at his Instagram. He doesn't just do animals, his portfolio is quite broad, but his style remains wonderfully consistent.