This tube displays how many blocks the player is holding, and when it is empty, no blocks can be placed. Up to 15 blocks can be stored in the tube, and once it becomes full, no blocks can be erased unless a stored block is placed somewhere else on the screen (thus freeing a space in the storage tube). There are many different types of blocks in the game, each of which has its own special effect.
The tube displays how many blocks a player has and prevents placement when it's empty. It can store up to 15 blocks; once full, no block can be removed unless another is relocated elsewhere on the screen (thus freeing space). The game includes various types of blocks with unique functionalities.