Optimization strategy used by Louis's substitution-cipher solver. Start from a frequency-seeded key, repeatedly swap two letter mappings, and keep the swap if the quadgram score improves. To escape local maxima, periodically accept a worse swap — but decrease the 'temperature' (probability of accepting regressions) over time so the search explores early and exploits late. Each Ractor used an increasingly aggressive cooling strategy: the first Ractors explored freely, the last Ractors stuck rigidly to strict improvement.