"book-pflow-xyz/chapters/appendix-d-glossary.md" . . "A place that no move takes a token back from: once a token arrives, the transitions that wrote it never consume it. History places are the canonical case — `X11` and `O02` in the tic-tac-toe net of Chapter 6, `_D2_01` in the Sudoku net of Chapter 7. Their only downstream transitions are the pattern and constraint collectors that turn a completed pattern into a verdict. The smallest instance of tropical accumulation (Appendix E)."@en . . "Write-once place"@en . "6"^^ . "7"^^ .