Level 143 solution

Solver-verified route

1. Place the stack from Slot 3 onto hex (1, 1).
2. Place the stack from Slot 2 onto hex (2, 0).
3. Place the stack from Slot 1 onto hex (-1, 0).
4. Place the stack from Slot 2 onto hex (2, 0).
5. Place the stack from Slot 3 onto hex (0, 2).

The solver clears this board in 5 placements. Hex coordinates are axial (q, r) from the board center.