A long, long time ago, when everything was just starting out, and even the planets and stars were so young that they were still going to school, there was a special class which was everyone's favourite, having by far the most fun classmates. The class members were a bunch of rather mischievous colours; from black and white, through to red and blue, yellow, and all the rest. They hoped to grow up to be wonderful colours, and this is what they were training for.

As well as funny and joyful, the colours were very naughty; particularly black and white, who were so preoccupied with causing mayhem that they were almost always late for class.

One morning there was a great commotion in the sky. The clouds were up there, practicing their raining, but they had been raining for so long that they'd gone and created a storm so terrible that absolutely everyone had become saddened and depressed at having so little light. When the sun started shining again, not even that managed to cheer up the world.

The only solution was to appeal, as a last resort, to the naughty, mischievous colours, even though they were still very young and weren't yet trained for anything like this.
The authorities went straight to their classroom. It was still early, and, as ever, black and white hadn't yet turned up.
However, there was no time to lose; they couldn't wait for black and white. The other colours had to do something fast. They ran down the corridors, out of the door, and flew up into the sky, where the clouds - ashamed for what had happened - were waiting.

On their way up to the clouds each one of the colours left a resplendent trail.
Travelling side by side, the combination of all the colours' trails was so striking and spectacular that smiles returned to everyone's face, and the world filled with the sound of applause.

The colours felt honoured and delighted to be named as the sun's official assistants. And the inhabitants of the world begged them to promise that, from that day on, the colours would always be on hand, to help cheer everyone up. It was agreed that whenever the clouds overdid it on the rain, the colours would come quickly and make a rainbow.

A bit later, black and white entered the classroom, finding it empty.
Everyone was congratulating the other colours so much for their wonderful performance that black and white - really the most fun and happy of all the colours - didn't dare to ask to be part of the rainbow, and from that time onward they forced themselves to be punctual and responsible.

Indeed, they managed this so well that now they don't mind being left out of the rainbow. They are now the most serious and important of all the colours, and no one can get anything done without them.