“Screw Puzzle: Nuts and Bolts” is a fun and comfortable mechanical puzzle game. The player sits on the grounds by turning colorful wood and metal parts with mouse or finger and attach screws to crevice. The target at each level is to fix or remove all metal parts accurately. There is no time limit, so children can think comfortably. Increases levels with different challenges and complex regulations. Natural wood pattern background and light sound effects create a calm atmosphere. This game improves hand-eye coordination and logic skills fun.