Bebop to the Boolean Boogie, 3rd Edition

Appendix D. Gray Codes

Gray, But Not Gloomy

When moving between states in a standard binary sequence, multiple bits may change from 0 to 1 or vice versa; for example, two bits change value when moving from 0010² to 0100². In the physical world there is no way to ensure that both bits will transition at exactly the same time, so this system may actually pass through an intermediate state. That is, our intended state change of 0010² to 0100² might result in the sequence 0010² to 0110² to 0100², or possibly 0010² to 0000² to 0100². And if more bits are changing, we might bounce though a series of intermediate values.

One way to avoid this problem is to use a Gray code,^[1] in which only a single bit changes when moving between states (Figure D.1 ...