Was just telling my friends, had one of those instances where I lost a run, so I closed the game with the intent of going to go so something else, then found myself opening it again 2 minutes later… so addictive

Yep this and/or wheel weights or buckshot

Edit: also might add some sort of grippy, non-slip material to the bottom so it’s not entirely relying on sheer weight. Also, hot glue can secure the weights in the cavity so they don’t rattle.