So far, on a 8x8 LED matrix, I have only seen the time displayed with scrolling numbers (beside the geeky binary/hex/tix/dice/dots/bars or other coded formats). There is simply not enough room to statically display 4 digits at once, since the tiniest set of human-readable digits can be defined in a grid not smaller than 3x5 pixels. I challenged myself to find an intuitive way to display 4 digits on the "standard" 8x8 matrix. I figured that this is possible if using 2 colors. Even though they may overlap a bit (quite literally), digits of different colors can be easily distinguished. This is because the overlap makes a third color: in the case of the bi-color (red/green) LED matrix, it will be orange. I focused on two aspects: font definition (3x5) as simple as possible, with minimal number of "on" pixels, but still readable; // tiny 3x5 digits; byte digit[10][5] = { {2, 5, 5, 5, 2}, // 0 {1, 1, 1, 1, 1}, // 1 {6, 1, 2, 4, 7}, // 2 {7, 1, 2, 1, 6}, // 3