Blog

Notes from the archive.

ShuffleArchive records simulated riffle shuffles and checks each one against every shuffle before it, hunting the first repeat in history. These essays are what the project has learned along the way: probability at scales intuition cannot reach, and the engineering it takes to make a claim like “never repeated” checkable.

September 12, 2026

How We Checked 12.3 Million Shuffles Against Each Other

Comparing every shuffle with every other means 75 trillion pairs. The engineering that makes it instant, from a 52-byte deck encoding to exact byte comparison.

September 12, 2026

Has a Shuffled Deck Ever Been Repeated?

Almost certainly not, and we run the only project that tests it. Every recorded shuffle is checked against every shuffle before it. Zero matches so far.