Floyd Mayweather -- Insane Layered Sculpture ... From Famous Artist

This is a pretty bad ass birthday gift!!

Floyd Mayweather turned 38 yesterday ... and to honor the boxer, famous artist Michael Kalish whipped up one of those ultra-cool layered sculptures of Floyd's face.

If you haven't seen one of these before, they're awesome -- comprised of multiple pieces set apart from each other in layers -- but when you look at it head on, they all come together to form an image.

Kalish says the sculpture took four months to put together and cost $75,000.

Mayweather received the gift at a bowling party in Vegas ... and you can tell the guy is clearly impressed.

Kalish tells TMZ Sports, "I will be at the upcoming fight against Pacquiao, but I won't be the next Justin Bieber, walking in next to him."