This archive provides a minimal and clean Python implementation of the Collatz‑12 (Duodecadia) dynamical system.The Collatz‑12 map is defined by twelve modular rules based on n mod 12, combining division operations (÷12, ÷6, ÷4, ÷3, ÷2) with acceleration operations of the form 13n ± c. A distinctive feature of the system is the Outer Rim, consisting of the residue classes{1, 5, 7, 11} mod 12, where all ×13 accelerations occur.Among them, Class 7 acts as the strongest accelerator and is known as the Sanctuary. Although all orbits eventually converge to 1, many numbers exhibit long, glider‑like behavior by repeatedly returning to the Rim and producing large peak values before collapsing.This archive includes tools for analyzing such Sanctuary‑driven dynamics, identifying “Sanctuary Children,” and exploring near‑escape behavior. This archive includes: A Python implementation (collatz12.py) Documentation files (overview, how‑to) A plain‑text README for long‑term preservation A CC BY 4.0 license The purpose of this dataset is to support reproducible research, numerical experiments, and exploration of dynamical behavior in the Collatz‑12 system.