Level 85 solution

Solver-verified route

1. Place Piece 1 across column 7 row 1, column 6 row 2, column 7 row 2.
2. Place Piece 3 across column 4 row 2, column 3 row 3, column 4 row 3.
3. Place Piece 2 across column 2 row 1, column 2 row 2, column 3 row 2.
4. Place Piece 4 across column 5 row 1, column 5 row 2, column 5 row 3.

Part of the "Corner work" chapter. The solver certified 24 solving lines with 96% of in-between placements being dead ends, for a difficulty score of 15.2 (grade 2 of 5).