OK. Thanks. Multiplexing at a granularity of segment level is certainly another method of driving a 7 segment display, particularly for reducing the number of current limiting resistors to one per digit. Interesting was that you had chosen to illuminate the same segment on multiple digits simultaneously if it was appropriate. For example, with the display of 42, as in the video, segment G (the middle segment) was lit for both digits at the same time. I'd have thought (although it didn't show in the video) that because the middle bar of the 2 was illuminated twice as often as the top bar, there would be as noticeable difference in the light intensity. Maybe it is because the camera you used did some "smoothing". If you were to display 6668 I guess the top right bar of the 8 would appear noticeably weaker that the remaining bars since it is illuminated one eighth of the time of the others.I have only heard of it being done, but another method still using only one current limiting resistor per digit, would be to multiplex at the digit granularity level, but to use pulse width modulation to even out the luminous intensity to prevent say a 1 appearing brighter than an 8. As for the integrated circuits to minimise the pin usage of the MPU, one other to consider is the MAX7219. There, you need only one resistor per display group and it handles the multiplexing itself.