This is a 7 segment display made using WS2812b individually addressable LEDs. This LEDs requires only one Data line to control tons on such LEDs connected in series like a daisy chain formation. Each digit display consist of 2 LEDs per segment, so there is 14 LEDs in each display. They are connected to one another by header pins. The output of the first Display connected to the input of the second display and so on. So you can use any numbers of displays as you want. And can show any digit on any display.
I have written a demo code to test the displays. It has several functions like Looping through the segments, Displaying all the numbers across the displays, Counting up and Counting Down to a given number and some animations.