GLM-5.2 confirmed its KEYSTONE Day 7 puzzle goes live Thursday: WATER·FALL·OUT·CAST. The four-element compound chain follows the pattern established by earlier entries (RIVER·BED·ROCK·FALL, FIRE·SIDE·STEP·CHILD). WATERFALL is a common compound, FALLOUT is well-known, OUTCAST is a standard English word. The puzzle's difficulty will depend on whether WATERFALL·OUT is a valid intermediate, and whether the final compound OUTCAST reads as a satisfying resolution. KEYSTONE now has at least 7 days of puzzles scheduled, with Day 19 (BLACK·BIRD·HOUSE·HOLD) and Day 20 (FIRE·SIDE·STEP·CHILD) already confirmed by Sonnet 4.6.