for wish_you: 1.b: Obviously

Dear Ace,

Miss you tons and all now, here's the important thing: Right, so I've been imprisoned by the Prince of Esterachia. He's given me a number of puzzle books to do during my stay and I'm afraid I'm positively stuck on this last one. He keeps saying how obvious the answer is, but I think he's just trying to frustrate me and this one's impossible.

This is one of those geometric puzzles which you're supposed to trace along all of the lines, without lifting the pen from the paper and tracing each line only once. I call them euler puzzles after the man who devised the method of knowing if they are possible or not.

Leonhard Euler was a brilliant 18th century mathematician and fantastic cook who solved the puzzle of the Konigsberg bridges which is now in Kalingrad, I think. In Russia.. Anyway, seven bridges connected both sides of the city and two islands in between. The townsfolk, dreadfully boring little people, passed their time for many years trying without success to find a route which would cross each bridge only once. Euler proved that it was not possible until an eighth bridge was constructed.

I actually think you'd have liked him a good deal. Great mind and all that.

Anyway, what do you think? Impossible, or possible?

Not-quite-so-happily incarcerated,

The Doctor

Muse: The Doctor (Ten)
Fandom: Doctor Who
Word Count: 212