That's what flash memory does, it can store four bits per cell (quad-level-cell) https://en.wikipedia.org/wiki/Multi-level_cell https://en.wikipedia.org/wiki/Mu

That's what flash memory does, it can store four bits per cell (quad-level-cell) https://en.wikipedia.org/wiki/Multi-level_cell https://en.wikipedia.org/wiki/Multi-level_cell The Intel 8087 math coprocessor stored two bits per transistor in its microcode ROM. It used four transistor sizes / voltage levels. This was necessary to fit the microcode on the die. https://www.righto.com/2018/09/two-bits-per-transistor-high-density.html https://www.righto.com/2018/09/two-bits-per-transistor-high-...