You are Sergey and you are hardly working for an extremely low eCPM in the Tetra Block Factory, Production Department, 3rd night shift. Your job is to continuously detect and fix defective tetra-blocks which will be delivered to the Tetris game. How much blocks can you fix before you make a mistake? Remember, the blocks are getting more and more defective and you only have the one chance! Here are the main steps of your job: Select a defective block from the conveyor belt by clicking on it. Fix the selected block by clicking on its bad fields and try to match the pattern that is displayed over the selected block on the conveyor belt. Return the fixed block to the conveyor belt by clicking anywhere outside of the fixing area. Try to fix the block before it falls out of the conveyor belt as a defective block, otherwise the game is over!