"KITT I need you buddy".
One logic source gives the pulses to the counter. The other logic source running with 12x period changes the direction.
The logic gates are implementing a 4-to-7 multiplexer. The output of the counter initializes with zero, when the simulation starts, but right away the next impulse will set it to 1, so the multiplexer should work in the following way:
A B C D Output
1 0 0 0 first led high
0 1 0 0 second led high
1 1 0 0 third led high
0 0 1 0 fourth led high
1 0 1 0 fifth led high
0 1 1 0 sixth led high
1 1 1 0 seventh led high
Project Knite-Lite from '84: https://cdn.instructables.com/ORIG/FEE/P7J5/IQ6UOGDJ/FEEP7J5IQ6UOGDJ.pdf
