Comment by Promarged

This paper [0] (from 2013) linked from this article [1] was also executed on chain, see date here [2] and the actual script via API here [3].

[0]: https://eprint.iacr.org/2013/784

[1]: https://curiosity-driven.org/bitcoin-contracts

[2]: https://blockexplorer.com/tx/7ae5760af2105a5ba54a914f188686e...

[3]: https://blockexplorer.com/api/tx/7ae5760af2105a5ba54a914f188...