Well I don't remember being naughty last year, but even so, I got this messed up digital clock from Santa. Is it because I'm not a christian? Or maybe because of my stupid comment? I just don't know.

The clock displays the digits in a weird way. Here are some examples of random digits1 displayed by the clock:

An example of some digits

I told my cousin (who is an electrician) about it, and after taking a look at it, he told me that the clock is working perfectly fine, but its 7-segment displays are wrongly assembled. I asked him if he could fix it. He couldn't and said it was some complicated elf craftsmanship. So the only thing left for me to do is to learn how this clock displays the digits (0-9) so I can read time properly. I've been trying to figure this out on my own since then but with no luck.

I really need this clock because I gave my old one away. Now I'm either too early or too late for everything. Please help me read time using this stupid clock. Here I made a sheet2 that you can fill once you're done. I should tell you that I'll accept your answer only if after reading it (the answer) I will be able to read time correctly.

Hint #1:
This is already deduced by @Deusovi in his answer down below, so I might as well just add it here so it becomes official.

I tried contacting Santa and the elves via their Customer Service Office. They didn't say much, but they told me that D is OBVIOUSLY 8. When I told my cousin that, he said: "Not only are the segments are misplaced, but they're also inverted (ONed when they should be OFFed and vice versa)."

    1. The letters above the digits are not related to the puzzle. They are there just for referencing. So to refer to the third-from-the-left digit you could just say C.
    2. Flood-filling works. When you're done, just flood-fill the segments that should be ON with black.


1 Answer 1


One possible problem with your clock is that:

all the segments are inverted and moved around.
To fix it, you can permute the segments like this:
enter image description here
When you rearrange your segments to fix it, the red segment on the left goes to the red segment on the right, and similarly for the other colors.

Unfortunately, there's not enough information from the original digits to tell which of the gray segments on the left go to which on the right. So there are two possible ways your clock can be read.

In its current state, here's how you would read your clock.
enter image description here
For the 7, either one of the two lightly-shaded parts can be filled. There's no way for me to know (but you should be able to do it just fine!)

  • $\begingroup$ Shouldn't a zero just have the top line "ON"? (Argh, I am getting confused by this.) $\endgroup$
    – YowE3K
    Commented Jan 7, 2018 at 4:42
  • $\begingroup$ @YowE3K Not the top, but the bottom. (I went the wrong way with the transformation -- my fault for writing it that way.) Fixed now, though -- thanks! $\endgroup$
    – Deusovi
    Commented Jan 7, 2018 at 4:44
  • $\begingroup$ I think your edit got mixed up. (Not sure whether it is right or not, it's still different to what I am getting.) $\endgroup$
    – YowE3K
    Commented Jan 7, 2018 at 4:49
  • 1
    $\begingroup$ What I meant was that dark blue should be light blue and vice versa (in one of the sides of the transformation, either source or target). For an easy way to see that your current chart is wrong: digit B is nowhere to be found in your chart. $\endgroup$
    – ffao
    Commented Jan 7, 2018 at 5:20
  • 1
    $\begingroup$ Sigh - I had my 6 back to front so I needed to redo my drawing to fix that, and then your final version beat me by 1 minute :D $\endgroup$
    – YowE3K
    Commented Jan 7, 2018 at 5:26

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.