How many iterations did you have to go through to find it?
Yo, where my nerds at?!!
I created a bitcoin mnemonic that starts with "coffee".
Its fingerprint is c0ffee4b
It has a receive address that starts with 3Coffee
That address wrote an OP_RETURN that says "c0ffee inception!"
And the txid of that transaction starts with... c0ffee!!!
https://mempool.space/tx/c0ffeebcb6682294ebe29f06e0afb790f23f551d5c592b59bce1ccaffe128049
Discussion
Have to grind / brute force for every part. I can't remember how long the mnemonic took to get one that yielded a c0ffee fingerprint, but it wasn't too bad. A 6-char hexadecimal match is over 16^6 possibilities so not too bad, but the bip39 calcs make each iteration slow. Probably did ~50 million over a few hours?
The 3Coffee address was the killer. Nested segwit addrs use base58 so a 6-char target is 58^6 possibilities. Had about 10 threads running for 2-3 days grinding address indices. About10.2 billion attempts.
(everything would've been probably 1000x faster if I did this in rust instead of python, but taking on rust would've been too ambitious)
Then the c0ffee txid was probably the easiest part. The end of the OP_RETURN has a random hexadecimal string; that causes the transaction to hash to a different txid each time. That only took about 2hrs of grinding while I made lunch today (an easy 4.4 million tries)!