OpenSSL version must be 3

[PlayLikeNeverB4]

I tried running pictoprime on OSX and I had this openssl installed

> openssl version
OpenSSL 1.0.2q  20 Nov 2018

which only returns the hex value and not decimal

> openssl prime 12321321                                                                                                     
BC0229 is not prime

which resulted in the ascii art to be incorrect

After I used openssl@3 it worked

> /usr/local/opt/openssl@3/bin/openssl prime 12321321                                                                                   
BC0229 (12321321) is not prime

So if anyone else runs into this issue you know how to fix it and maybe we can adjust the README to mention this.

[funatparties]

I had a similar issue on Ubuntu 20.04 with openssl 1.1.1f but only for larger primes (~ above width 50 for taller images). Upgrading to openssl 3 did fix it.