How exactly would you do that? 3 states need 1.58 bits which is a tad more than 1.5. Two 3-states have 3²=9 states while three bits only give you 2³=8 states.
I wonder if there's some encoding tricks you can use to reduce it to 8 (or less?) effective states, given that you're only using them with a reduced set of mathematical operations. E.g., can you automatically convert all (-1, 1) to (1, -1) and save one encoded state, since they add up to the same result anyway?
