Done! I've made two fixes:

1. **Added a larger stopper** (radius 0.7) positioned at `(tableWidth/2 - 1.5, tableHeight/2 - 0.2)` to block the gap between the right guide wall and the outer wall, preventing the ball from falling through.

2. **Shortened the launcher wall** from 65% to 55% of the table height and repositioned it further back (z position changed from 0.175 to 0.225), so the ball won't hit it when returning down the play area.