I went to a party where I had to wear something from the 80s so I bought these Tetris water stickers from Ebay. How "rad" are they?
They were a bit fiddly to put on. First I applied the nail polish and allowed it to dry. Then I cut out the blocks (individually as I have small nails) and soaked the pieces in water. They absorb water completely in 30 seconds so it's really easy to take off the paper backing with a tweezers.
I laid the blocks where I wanted them to go one nail at a time and blotted away excess water with a tissue. The decals stuck really well. When all nails were done, I applied a top coat. And voila, Tetris nails!