Most people are likely within about 20 feet of a 7-segment display right now, whether they realize it or not. These displays have been a commodity for many decades at this point, although people are probably not aware that '7-segment' is the formal name for the displays they see every day. The term comes from the 'segments' of a display that's built into your microwave, your oven, alarm clock, even your digital watch if you still rock an old-timey pre-smartwatch.
The term comes from the layout of the display itself, as it is arranged in segments. There are seven segments in total, and the number '8' is represented by turning all 7 segments on. '0' turns all of them on except for the center segment. '1' turns only the two furthest right segments on. And so on. Hopefully this quick explanation makes sense- it's one of those weirdly esoteric sounding terms that actually turns out to be really simple and very literal when you realize what it means.
Seven-segment displays are pretty ingenious in their design, so simple at their core and they do the job extremely well. Well enough to have become common enough for most humans to have seen in their daily lives. But there are other designs out there, ones that try to push the envelopes of that simplicity and ingenuity. Which leads to some pretty mind-bending rabbitholes. Such as the six-segment display.
The six-segment display is a peculiar design concept. It seems simple. I mean, you can take off one of those lines in a 7-segment and arrange them uniquely to represent all 10 numerical digits right? Well... it's a bit deceiving when you actually try to implement a practical design.
The below picture was my first quick attempt to try and come up with an arrangement.
This below was my second, a more professional arrangement because I thought "I was close free-handing it, let's standardize these".
But that zero is the catch. That's exactly where 6-segments become so complicated to implement. How can you use just 6, and arrange them in a way that any normal, untrained person could recognize a 0 or an 8 or a decimal (period) natively? So my third attempt was made below.
I'm going to go into a deep-dive on display technologies, but for now I just want a place to document my attempts. This was just a curiosity, and the neat part was I came pretty close to other people's designs when I went looking for already existing stuff. Examples like these:
If you're curious about this concept yourself, check out this awesome post at Hack-a-Day to learn more about 6-segment display technology history: