a) active cycle entry, b) swap operation, c) in-place cycle

Color Cycling refers to a Palette Swap effect where one or more entries in a palette are sequentially swapped with an active entry from another (or the same) palette.

The active entry/index in the other palette is increased or decreased periodically and wraps around to the other end when it goes out of range: it “cycles” across a range.

The cycle for indices 7,8,9,A in the example here could also be implemented in-place.

further reading:

• Color Cycling
• HTML5 Color Cycling Demo - featuring art by Mark Ferrari and code by Joseph Huckaby