NONCE.
a brainfuck program is only valid once its file hashes to a run of leading zero bits — hard to write, trivial to verify.
target: k = 8 leading zero bits
01
Write
standard brainfuck
checking…
02
Encode & find nonce
the nonce-finder tool
+[.+] <nonce>
Valid once SHA-256 of the whole file begins with 8 zero bits — roughly 1 in 256 candidate nonces qualify.
03
Validate & execute
paste any Nonce source