Why are "Follow Me" cars painted black and yellow, and use square shapes in their design?
Yellow and black together are highly visible in any light, especially if there are sharp, straight lines between them; our eyes are drawn to that combo and our brains are evolved to recognize it as a danger. Think of bumblebees.
Stationary objects tend to be painted white and red for similar reasons.
It is because when you are taxiing behind the follow me in a dark night with a dark pavement it will make the car become more easy visible to the pilots, specially in low visibility operations