Imagine you have a three way intersection and a your friend from the government hires you to make a three way traffic light
Now you will start thinking…. “how do i make this?” well fortunately you have your friend karnaugh and your basic knowledge from school so:
If there is no car on any street green street light A will remain on as it is the main road.
If no vehicles in A, but B and C , then B have right of way so that its light should be green and those of A and C in red.
If there are only vehicles in C , then the light of this one has to be green , and A and B should be red.
If there is no presence of vehicles on the 3 blocks (A, B and C ), A has the right of way , so its light ( which is diagonal to the mouth – street) has the green light and the B and C they are in red
But what about the yellow light?
well, that one is up to you!!