In a far, far away mathematical kingdom there lived three inseparable mates: Ruler, Triangle and Compass.
They lived across the land of Mathematics, in an old castle-pencil case. There were many inhabitants in this land: different geometric shapes, numerals, all arithmetic operations, and notebooks. There were many of them, but they lived harmoniously and always rushed to help one another, though they did love to argue amongst themselves about who was the most important.
And so one day our friends decided to pop round for tea at Square, who lived nearby.
Square lived in a new, recently built palace. The friends were so impressed by the building that they too wanted to construct themselves a new and spacious home, as their old castle was becoming increasingly dilapidated: the corners had warped, and the roof was about to collapse.
At a home meeting the friends divided up the tasks, agreeing on who would be responsible for what during construction. Ruler volunteered to build the walls, Compass – the roof, and Triangle got the windows and doors. All together with doubled effort they set about the construction.
But it wasn't all straightforward! When the construction was in its final stages, the friends noticed – the house had come out crooked. They would have needed to work out all the details again, but the mates, having started to figure out who made the mistake and where, who amongst them didn't know the rules of calculations in house design, had a row. And they scattered, tired and upset, to their respective sections of the pencil case castle.
But the next morning Protractor, Notebook and Pencil came to help them from the same mathematical kingdom. Having taken all the measurements and verified the angles were correct, Pencil with the help of Protractor carried out all the calculations and workings, sketched out a construction plan in the notebook.
Compass would now be responsible for all measurements down to the millimetre, Ruler builds the walls and roof, and Triangle is responsible for the correctness of all the house's angles.
Heeding the advice of their mathematical friends, the drawing instruments built a new, straight and beautiful home. It turned out to be the correct shape, with new technical results. From that time on in the kingdom of Mathematics, they build and do all calculations only together!
