What's a good (preferably simple) nerdy / programmingy thing to carve into a pumpkin? So far, I'm thinking a stylized lambda

The set of all pumpkin carvings that do not contain this pumpkin carving.

The scariest thing for programmers: Legacy code No documentation Single letter variable names

I love single letter variable names

the monad laws

some APL code

So far @Ivan Reese is the winner. But keep trying..

P = NP

Hot take: Pumpkin carving is imperative, not declarative. My suggestion is definitionally simple, but procedurally difficult to carve. Very difficult.

Maybe a lambda in parenthesis Or if I want to resonate with more people, a simple pi (... On a pumpkin...)

The power symbol is a good one too

The Y combinator.

Y f = f (Y f)

or

Y = λf.(λx.(f (x x)) λx.(f (x x)))

. Scary because: (1) can be used to demonstrate that untyped lambda calculus is unsound as a deductive system; (2) causes an infinite loop when applied to most functions; (3) single letter variable names.

Does laser etching work on a pumpkin?

Laser cutters don't work well because the pumpkin doesn't have a flat surface, and the laser is only focussed over a short interval. Also, the entire pumpkin needs to be inside the machine for laser safety. But CNC mills work just fine.

A friend of mine was also thinking about the process a lot. Result: https://www.instagram.com/p/B4Qf5DupyYn/?igshid=198egj1b7u1rd