@wyliesau @white_male @BowsacNoodle
Ooh, this is two things I know about.

The cathedral has what's called a foot maze or, more commonly, a walking labyrinth. They're a meditation/prayer aid so you can calm yourself TF down a bit. The more pious types back in the day would do them on their knees (think old school monks and the like from pre-electricity days). There's a few around here up in the mountains, some dating back to the early/mid 1700s.

As for the circuit board, an antenna seems a likely explanation, and this was someone bekng cheeky with the pattern.