It seems to me that, logically, two squared plus three squared should equal (two plus three) squared, but it doesn't. I have spent a long time trying to find the fault in my logic and I think I have it - at last! (I have tried writing those figures in a word processor and pasting into Blogger but the little 2 meaning squared doesn't come out properly.)
Back to that list of 50 Things to Do Before You're 11¾ two days ago. Buck commented that he had to Google a number of them. He's not alone. "Wild swimming" was something I had never heard of but I guessed it meant swimming in the sea, a river or lake. I was right. But I still don't know what a grass trumpet might be.