Recently at my workplace the water coolers and the water boilers have been replaced by a machine which does both. It's very simple. It has a green light to indicate it is on. If you press the big button you'll get icy cold water. And if you press the small button on the left, the green light turns red to indicate there is enough hot water and that by (quickly!) pressing the big button before the light turns back to green you'll get hot water.
Great. Apart from the short time you're given to acquire the hot water when it is available, can you see something else that is flawed in this design?
A light that changes between red and green. Most colour blind people can't distinguish between the two. Great. Now how do they know whether there is hot water, other than by sticking their finger in the either freezing cold or scolding hot stream of water?
But it is even worse!
Because there are not two colours! There are three! Apparently the light turns yellow as well. I'm colour blind, but have no problem with red and green. Green and yellow on the other hand...
The above is how I thought the machine worked, but for people without my kind of colour blindness, it apparently works like this:
The light is yellow to say "there is no hot water", green to say "there is hot water" (or was that the other way around? I can't remember, and I can't check, because I can't tell the two apart!) and red to say "thanks for pressing the small button on the left and as a thank you I might just give you hot water if you press the big button. But only if you're quick enough."
Stupid design.
