If you're not familiar with binary, this tutorial should help you to easily read the Pyramid Clock.
Binary display
Binary is a way to represent information using only two states ("1" and "0", "on" and "off", etc.). For example, the number 6 in binary is "110". So the number 6 requires 3 bits for a binary representation.
The Pyramid Clock uses 11 bits to display the time in binary form. Each bit is represented by an LED light: the top row has 1 bit for AM/PM, the middle row has 4 bits for hours (0-12) and the bottom row has 6 bits for minutes (0-59). Turns out that 11 bits is the minimum amount of bits you can use to represent time (not including seconds).
Binary form can get pretty long as you count up, so it's helpful to have an easy method of reading longer numbers. One method is to understand that each bit in a binary number represents a power of 2 in ascending order from right to left. For example, the number 6 is 110 which uses 3 bits, and the first bit is the right-most bit (the "0" in "110"), and the last bit is the left-most bit (the left "1" in "110").
So you read it right to left, where the first bit is counted as 2^0=1, the second bit (moving left) is counted as 2^1=2 and the third bit is 2^2=4. You can see that "110" is 6 by looking at each bit and adding up their value as a power of 2. So the first bit is "0" which means it has no value to count, but the second bit is "1" so you can count it's value as 2^1=2 and then you add to that the value of the third bit which is 2^2=4. Restated, the value of the second bit is 2 added to the value of the third bit which is 4, 2+4=6. Done.
Now let's try a harder one:
100011
In this case, you have 6 bits. Let's look at what each bit value is:
| 1 | 0 | 0 | 0 | 1 | 1 | <-- binary number (6 bits)
|32 |16 | 8 | 4 | 2 | 1 | <-- values for each bit
32 + 0 + 0 + 0 + 2 + 1 = 35
Now you have all you need to be able to read the Pyramid Clock. After trying a few times you will see that it gets pretty easy. Let's look at an example of the clock display. By default the AM/PM bit will display as yellow for "1" and completely off for "0". Hours are the 4 bits in the middle row, displayed as green for "1" and faint white for "0". Minutes are the 6 bits in the bottom row, displayed as blue for "1" and faint white for "0". See below.
Example clock display
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* * * *
* * * * * *
Above we have the clock displaying 6:45pm.
"1" at the top for PM
"0110" in the middle row for 6 hours (0+4+2+0=6)
"101101" in the bottom row for 45 minutes. (32+0+8+4+0+1=45)
Hopefully this tutorial has given you the confidence to tell the time in binary, and with little practice you can tell time with a quick glance at the clock.