Description: 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 !

Instructions: Use your mouse to select and fix all defective blocks before they fall out of the conveyor belt.