Knight check at an uncastled king walled in by its own pieces
A knight checks a king that has not yet castled, with the king's own pieces blocking every escape square. The classic shape: a knight on c7 (or its mirror) attacking a king on e8 with own rook on d8, own bishop on f8, own pawns on d7 and e7. Pure smothered logic, but in the development phase rather than after castling.
Rook sacrifice on d5. Removes the knight defending the king.
Go on then, take it.
3 more clean runs (at any point) to reach Recall.
Knight on e6 ready to spring. The king sits on d7 with pieces all around.
3 more clean runs (at any point) to reach Recall.