Quad-level flash memory cells (https://en.wikipedia.org/wiki/Multi-level_cell#Quad-level_cell https://en.wikipedia.org/wiki/Multi-level_cell#Quad-level_ce...) c

Quad-level flash memory cells (https://en.wikipedia.org/wiki/Multi-level_cell#Quad-level_cell https://en.wikipedia.org/wiki/Multi-level_cell#Quad-level_ce...) can store 4 bits for months. Because of that, I would (hand-wavingly) expect it can be made to work for a three-bit adder (with four bits of output)