I am hopelessly behind with work, on account of (a) 2 wks vacation, and (b) having hit a particularly time-consuming patch in the book-production process. (I actually hit the patch the week before leaving on vacation, which makes everything nine times worse.)

Among the things I’m behind with, as several readers have reminded me, is posting a solution of the math puzzle at the end of my July Diary. Sorry.

In fact, sorrysorrysorrysorrysorry.

The minimum normal goes from (2, 2*sqr(2)) to (8, -4*sqr(2)), & has length 6*sqr(3). No, I don’t know a cute way to get the solution other than just by breaking rocks. I hoped some reader might, but none did. Like me, correct respondents all used high school calculus. The equation of the normal at (u, 2*sqr(2)) is x+y/sqr(u)-(u+2)=0, and you proceed from there.