The first versions of ASCII used 7-bit codes, which meant they could attach a character to every binary number between 0000000 and 1111111, which is 0 to 128 in decimal.

What does Gray code actually mean? ... Used in telegraphy in the late 1800s, and also known as "reflected binary code," Gray code was patented by Bell Labs researcher Frank Gray in 1947.

And now you have your 10-bit Gray-code using consecutive addresses of 0000-to-1001 (0 to 9 in decimal). In this case, the sequence followed by this Gray code counter implementation is: 4, 6, 2, 0, 8, ...

Inspired by naturally occurring air bubbles in glaciers, researchers have developed a method to encode messages in ice.