Tetris jewelry. Sold by TetrisGems -- apparently the official provider of Tetris jewelry -- the pieces feature real gemstones or cubic zirconia set in either gold or silver.
This is real jewelry, folks, with the cheapest pieces running $130 and the most expensive capping out at $450. And honestly, what better way to say "I love you" than with the gift of an L block? Why not get multiple pieces and fit them together? Just be sure not to connect too many pieces together or they might disintegrate.
Also, never give that special someone a line piece as their first romantic gift. You really need to save that for when the time is right.