An interesting discussion at Stackexchange. The question is:

I’m a children’s book writer and illustrator, and I want to to create a book for young readers that exposes the beauty of Mathematics. I recently read Paul Lockhart’s essay “The Mathematician’s Lament,” and found that I, too, lament the uninspiring quality of my elementary math education.

I want to make a book that discredits the notion that math is merely a series of calculations, and inspires a sense of awe and genuine curiosity in young readers.

However, I myself am mathematically unsophisticated.

What was the first bit of mathematics that made you realize that math is beautiful?For the purposes of this children’s book, accessible answers would be appreciated.

And here is a randomly chosen answer with other contributor’s comment:

A: I found it completely amazing that the angles in a triangle always added up to 180 degrees. No matter how you drew a triangle, you could measure the angles with a protractor and they always add up to about 180 degrees, like magic. Even more amazing when I realized it wasn’t some rule of thumb or approximation, but true in some deeper sense for the ideal, platonic triangle.

C: When I came home and told my father, he drew a triangle on the skin of an orange. All angles were 90°. I was deeply disturbed.