# A riddle of ice and fire dragons - Henri Picciotto

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TEDEd Animation

## Let’s Begin…

It’s your first day as Center Realm’s official cartographer, and you’ve already got a big problem. Center Realm is home to three elder dragons: two ice, one fire, and they’ve lived in harmony for centuries. But scouts have sighted three fire dragons and five ice dragons flying towards the region. Can you figure out where to place the new dragons? Henri Picciotto shows how.

## Additional Resources for you to Explore

You can find more map coloring puzzles, and some teacher notes for a classroom activity leading to the two color theorem on Henri Picciotto’s Math Education Page.

Mathematicians have long known that any map can be colored with four or fewer colors, so that each region contains a single color, and regions that share more than one boundary point have different colors. The four color theorem was proved in 1976 by analyzing hundreds of maps with the help of a computer. This riddle gets you to think about maps that can be colored in two or three colors.

You can read about the four color theorem, its history, and its place in mathematics on Wikipedia: Four Color Theorem.

Want more riddles? TED-Ed has lots of fun and challenging brainteasers in our Riddles Series.

TED-Ed Animations feature the words and ideas of educators brought to life by professional animators. Are you an educator or animator interested in creating a TED-Ed Animation? Nominate yourself here »

## Meet The Creators

• Educator Henri Picciotto
• Director Igor Coric, Artrake Studio