Collatz, but stop at the drop; Now with less noise

Take a whole number; halve it if it is even, otherwise triple it, add one and halve the result. Instead of asking whether every start reaches 1 (the Collatz conjecture), we stop at the drop: the first value below the start. Both questions are the same question. This paper tells the story as a game with two letters, 1 for an odd step and 0 for a halving, without proofs. Numbers that spell the same word up to their drop form a family, a residue class. The paper shows which words occur, how they are built from smaller words, how many there are for each number of odd steps (OEIS A100982), a faster way to play, and what is still open. The proofs are in the second paper, "Collatz, but stop at the drop; A game with two letters: the proofs", mostly formalized in Lean 4. The Python script pv.py replays every example.