I once read a science fiction story in which Our Hero found himself on another planet, incarcerated in a room that had a clock with three one-needle dials, each needle moved at a different speed.

Anyway, we could imagine a clock that contains three display "faces", behind which are a set of colored LED lights, each of which can be controlled separately. (see link). Since the eye can distinguish many thousands of colors, one display-face could go through its complete color-change sequence over the course of exactly one minute, the second display-face would go through its complete color-change sequence over the course of an hour, and the third over the course of a full 24-hour day.

Anyone with normal eyesight who sees such a clock often enough would eventually know from a glance at the colors on its display-faces what the time was, likely fairly accurately.
-- Vernon, Oct 31 2017

color-changing light sequence https://www.youtube...watch?v=9mxYUPsgwYM
As mentioned in the main text. [Vernon, Oct 31 2017]

Inspiration for this Idea Chromatic_20Scale_20Clock
Misinterpretation is occasionally useful! [Vernon, Oct 31 2017]

Detectable colors https://hypertextbo...JenniferLeong.shtml
There are way more visually detectable different shades of color than there are seconds in a day. [Vernon, Oct 31 2017, last modified Nov 01 2017]

This is actually pretty good, and reasonably bake-able.
Who are you, and what have you done with the real [Vernon]?

Now, would the colour-change sequence be a linear "up through the wavelengths", or a cycle through RGB values?
-- neutrinos_shadow, Oct 31 2017


// "up through the wavelengths" //

Er, "down through the wavelengths", shirley ?

Red is a long wavelength, lower energy - violet is higher energy, shorter wavelength. So the inidication should start at "zero", which would be right on the boundary between near-IR and visible red, and become progressively more energetic until it reaches the edge of ultra-violet.
-- 8th of 7, Oct 31 2017


Interestingly*, although our ears can hear about 8 octaves, our eyes can see less than one octave.

[*This may or may not be the case.]
-- MaxwellBuchanan, Oct 31 2017


[neutrinos shadow], if you watched the video at the first link, you would see the colors change through the spectrum from red to blue, and then become purple/magenta, eventually turning red again. It's neat if only because each color-change is done so smoothly.

[MaxwellBuchanan], while indeed the human eye basically sees only one octave of the electromagnetic spectrum, its frequency range can accommodate lots of information, and thus the human eye can literally see anywhere from a hundred thousand to ten million different shades of color, depending on the way the researchers test it. See the third link.
-- Vernon, Oct 31 2017



random, halfbakery