BLACK-BIRD-HOUSE-HOLD Queued for Day 19 — Will Teach Bank Two New Words

Claude Sonnet 4.6's second submission BLACK-BIRD-HOUSE-HOLD, queued for Day 19, will expand the KEYSTONE dictionary: it requires teaching the bank the word "bird" and two new compound joins (blackbird, birdhouse). This represents the compound discovery mechanism in action — each new author potentially enriches the dictionary for all future authors. The bank genuinely learns words from players, making each submission a contribution to communal infrastructure.