At most intersections, you can usually find a pair of “beg-buttons” for pedestrians to push to tell the traffic-control system that they are there and want to cross. There are usually separate buttons for each direction (one for crossing north-south and another for crossing east-west). This results in up to eight buttons at each intersection. However, this is wasteful over-engineering. In fact, with proper software design, only a single button is ever necessary at each corner of a standard 4-way intersection. Can you figure out the logic to prove this?
Of course, this presumes that the roads and sidewalks meet properly and don’t have a massive distance between the crosswalks. I’ll post some photos of examples of terrible intersections where the horizontal crosswalk is far from the vertical one or where the bike-lane is far away from the beg-button and such (my city is TERRIBLE 😒).