This is surprisingly good! One look at the thumbnail made me think it would be an illegible mess, but it turned out to be the MOST legible 4 segment display I've seen! Well done!
Actually the number of segments is minimally 3 if we count in central rotation. A 2 segment display with central rotation can also be made but it's far more illegible.
You need at least 4 segments because of the maximum possible combinations. Why? Well, lights can either be on or off, meaning that the formula to find the amount of possible combinations is 2^n, n being the amount of segments. With this, we can calculate by starting n as 1 and increasing until we find an answer over 10 (we need at least 10 to support 10 digits). 1 segment: 2^1 = 2 combinations. 2 segments: 2^2 = 2*2 = 4 combinations. 3 segments: 2^3 = 2*2*2 = 8 combinations. 4 segments: 2^4 = 2*2*2*2 = 16 combinations. Since 16 is more than 10, we can understand that we need at least 4 segments to support 10 digits. I apologize if this hurts your brain.
Its really good, but the rotation varies in a way that the 5 looks like a weird 4, and the 7 looks like a 7 from north korea who accidentally smudged a picture of kim jon un
