An on-chip latch-up protection circuit. Also provided are a use of the rubber composition and a main body comprising the rubber composition mounted thereon. The prompts are grouped according to relationships, obtained from the user input, among the tasks. A plug forcibly fits into an opening in the shelf while a key fits in a keyway to immobilize the track device relative to the shelf. The gaming system removes symbols from each winning combination, fills the empty symbol positions, and repeats as above.