Ignore the angles. Digital clocks don’t have angles anyway. Not the same angles, at least…
The first answer that comes to my mind is that the “shadow system” which I use for memorizing cards and various other things can not only capture nearly all of the 720 possible clock states in natural categories, but nearly all of the 1440 possible times of day which are represented by clocks (a.m. and p.m.). It actually would only include 1436 of them which is a lot more information than you need, but why hit backspace now? We’ve already moved on.
The shadow images have come in handy for so many more things than I would have predicted: chess, historic dates, letter combinations, license plates, URL’s, and Dewey Decimal by extension.
And now clocks!
You can get by with <1% of the imagery for your purposes, though. You’re asking for 24 pieces of imagery, or 48 if you care to distinguish between a.m. and p.m.
As usual, I’ll put to you that using the major system is your best bet.
1)Learn the major system.
2a)Extend it so that are 12 categories instead of only 10. The way that I tend to do this is to use the consonants “H” and “Y.” The reason that I do not include “Th” or “W” in these situations is that they are so audibly similar to “F” and “R” that I choose to represent them with the numbers ‘8’ and ‘4,’ respectively
2b)Alternatively, you could simply include 3-digit images using the Major System, the Ben System, or even the Dominic System if that’s the way you want to live your life. Just make images for:
10
13
20
23
30
33
…
110
113
120
123
- If you want to be able to differentiate between a.m. and p.m. (note that you will only need to do this if the clock-states must be recalled without context) then the easiest way to do this may be with shadow images.
A shadow image is an image that is related to the original image in any way that makes sense to you as far as being memorable.
996 - PBJ
s996 - Hamburger
For me,
123 - Tin Man
s123 - C3PO
Do you think this will work for you?