Thank you jono, that was fun. You did get me going with “jigsaw-wise” … I though we were going to get a grid of interlocking pentominos, all creating new words, Listener-style! Next time, maybe ;-)
Thanks Patrick. I borrowed “jigsaw-wise” from the preamble to Paul’s last alphabetical jigsaw in the Guardian, no. 28,285. The pentomino concept sounds interesting and it has just given me an idea!
Thanks, jono. Knowing you, I realized that there must only be one correct way to fill the grid, and I did spot "supporting" as the key. Well done. However, I still don't see "mechanical."