[racket] documentation example for slideshow/pict

   There is a mistake in your example, I've copied below a working
   one.  (renamed variable P to ph)

Thanks, Horace.  I wonder how I stuck that mistake in my post: it's
correct in my code, and it won't run with that busted P instead of ph.

   I think racket has excellent documentation. There seems to be a
   very fine line between overly verbose documentation and concise
   documentation.

I suppose you're right, but you (aren't you one of the maintainers?)
may not be a good judge of whether the documentation has enough
examples for the ''everyday programming'' folks Racket is targeting.

Did you look at the slideshow docs?  Was it was obvious from the
slideshow docs how to write my print-sudoku?  It took me a while :)
Did you look at the keybinding docs I complained about earlier?