Check out this presentation on non-binary computing! It’s for an entry for the Hackaday Prize, a competition to commemorate the 10th anniversary of Hackaday’s founding.
The presentation discusses ternary logic, a non-binary number system that uses three logical states instead of two. Ternary was used in the late 1950s as a practical way of constructing computers more efficiently. As the original Hackaday article notes, the 1950s Soviet ternary logic computer, the Setun, was able to compute more data using less vacuum tubes due to the use of ternary logic. It was more efficient.
You can read the full Hackaday article here.