Like me, you may have thought that Zero was a new setter since it was a name unfamiliar to me. However, the Listener web site reveals that he has had three before, back in 2007, 2008 and 2009. The last of these is one I can recall, having a theme about The Prime of Miss Jean Brodie. This week, it looked as though he was taking a leaf out of Jago’s Origami book, but we’ve got that to look forward to next week.

This week, fifteen answers didn’t fit their space, some straying into the central blank area, and sixteen had an extra word in the clue. Across words were thematic. The down ones spelt out something about axes, grids, approximate symmetry and perfect symmetry with a quantity to be entered in the grid together with a song title. Oh dear!

Luckily, I started off well. 1ac was EILD, and 14ac Lunatic owns where sermon was given, one in aircraft plant (17) was SNOW-ON-THE-MOUNTAIN, relatively straightforward courtesy of the lunatic owns at the beginning.

I won’t spend too long on detailing my solve, after all there’s an animation to orchestrate. However, while the first pass through the clues was relatively rewarding, it was a full 2½ hours before I could start construction. I was held up at the end by three clues. 20ac Hawk, perhaps, to make good donkey? (6) seemed to have donkey as the extra word, with REPAIR meaning to make good. When I finally got 3dn LOOT, I realised what a sneaky clue it was as we had to pin the tail back on the donkey! 23dn Sub prime expert with drive and bar degree (8) was also tricky, even though I could see sub for ADVANCE, but prime as a verb was a tad elusive.

In the centre of the grid we had Let’s Go Fly a Kite from Mary Poppins. The extra across words were all definitions of kite, and the extra down words gave us Aspect ratio of rectangle expressed as square root. Well, the grid was 17×12. Squaring that gave 289:144, which is pretty much 2, so that gave the ratio as √2.

Folding the grid to have the blank squares coincide gave the shape of a kite. Nothing too difficult with that. I hoped that Jago didn’t have anything trickier up his sleeve.

I believe that I have so far survived without having seen the Julie Andrews film, but that didn’t hold me up too much! Thanks for a nice bit of entertainment, Zero.