LegTris is a tiny portable Tetris clone with a twist: you're rearranging Lego bricks rather than the usual plain blocks.
The feature list is, well, short. There's no sound, no High Score table, not even any real instructions.
Fortunately the controls are very similar to just about every other desktop Tetris game: left/ right arrow to move a block, up arrow to rotate it, down arrow to drop it down immediately, P to pause and Q or Esc to quit.
There's also a not-quite-so common feature in that every falling block has a greyed-out shadow displayed where it's going to fall. Step left or right and this moves up or down to show how it'll fill a gap or leave one, perhaps helping you line blocks up correctly.