USE rises in one straight segment
Trace USE through 1 at row 5, column 3; 2 at row 4, column 3; 3 at row 3, column 3. The letters read U → S → E, and both moves go upward, so the path stays in one column without turning.
The starting cell has one open orthogonal neighbor, while the ending cell has four. This first route assigns three cells and leaves 16 of the board’s 19 open cells unassigned. Its row span is three and its column span is one, which gives you a compact check on the straight vertical shape.
There are two upward moves, no movement in any other direction, and only one straight segment. If your three-letter trace bends or changes columns, it does not match this route. The single edge visit occurs at the start, while neither endpoint is a corner cell.