The other day I passed a set of temporary traffic lights. Hardly an unusual occurrence in a modern city! This was a nice modern set, with the lights made up of an array of LEDs. That is of course a great improvement. Apart from the environmental benefits of being low-energy and long-lasting, the light area is evenly bright all over. And there can be no problem with low sun reflecting off the back mirror so it is hard to tell which colour is illuminated.
What struck me, however, was that the LEDs were carefully arranged in a circular pattern, mimicking the traditional look of traffic lights. This is clearly not the most efficient way of arranging them. That would be a hexagonal pattern, but of course you cannot produce what looks like a neat circular outline that way.
There is no reason why in an LED system each colour of light has to be round. They could just as well be hexagonal, or any other convenient shape. A hexagon would clearly match a hexagonal pattern better. Indeed, there could be advantage in making each colour a different shape, to help the colour-blind. They make the lights round because that is how we expect traffic lights to look.
Features that get overlooked
When looking at business improvements, there are usually aspects of the status quo which we retain and aspects which we decide to change. Some features are like the colours of traffic lights. The confusion caused by changing them would a serious problem, and we know we must not. Others may be like the type of light source. It is obvious that a change is possible if it is beneficial. However, some are like the shape of lights, which we are so used to that we forget to challenge them. We always need to be on the lookout for features kept because we forgot they could be changed rather than for good reason.