https://en.wikipedia.org/wiki/Seven-segment_display
Each segment is a LED. They are wired, from the circuitry, to present numbers from 0 to 9.
If one re-located the connections, the display would no longer look like numbers, as such, except for number 8 (which uses all the LEDs).
Below:
The first row shows how segments a to g is arranged to display 0-9 normal numbers.
Second row shows what the numbers would look like if wired one segment out of order.
Third row shows what the numbers would look like if wired randomly.
Note: how figure 8 remains the same.
If we substitute a segment for the decimal point (dp), number 9 will change, as seen in rows four and five.
They look alien don't they.
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Another use for such circuitry is to create a sort of random light display, of a computer, as seen in old movies.
Note: on the right display group of four, there are 7 squares per row.
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Here is a circuit that counts up or down. Clock and everything else is in one chip.
If one cannot make electronic circuits, then try rewiring an old clock display. To do so, first determine which wire is the common LED connection. The schematic above uses a common cathode, pins 3 and 8, and they are earthed, or connected to (-v / 0 v) of the power supply. Common anode display have their common LED lead(s) to the (+v). The other leads are for each segment.
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