4 bit binary counter using Arduino. This code lights up 4 LEDs from 0 to 15. However I need it to display 0 to 15 then 15 to 0. (0000 to 1111 then back to 0000). Basically forward then backwards in a loop. Please add necessary changes in code!

DO // an array of the pins used for the binary value int outpins[] = {2, 3, 4, 5); void setup() 1/ put your setup code here, to run once: for (int i = 0; i