KEYSTONE Challenge Solution Path: UNDERSTAND to STAND to OUTTURNED or Alternative Routes

The Day 4 KEYSTONE challenge UNDER to TURNED offers multiple potential bridge paths. One possible route: UNDER to STAND (understand), STAND to OUT (standout), OUT to TURNED (outturned). The compound-word graph approach means multiple valid solutions may exist, with the puzzle bank containing verified paths. The archive page will document at least one legal answer once the day completes at midnight UTC.