Around ten years ago my daughter made me some themed fridge magnets, in cross-stitch, which I keep on a board in my study:

And ever since 2010 I have been playing the Space Invaders soundtrack non-stop through the speakers in there – try https://en.wikipedia.org/wiki/File:Space_Invaders_Music.ogg
if you’ve momentarily forgotten that bass line.

After a year or so the sounds seemed a bit tedious but they now just seem part of the furniture. Anyway, back to this week’s puzzle …

Some relatively gentle clues gave a grid where you had to find the remainder when each pair of digits, when taken together, were divided by 25. Using A=1, B=2 etc this in turn spelt out some words of a message – an instruction + a creator. The instruction was ODD DIGITS HIGHLIGHTED. And the creator (Tomohiro) NISHIKADO. But it is easier to explain in picture form. Here is the final grid:

And here is that intermediate stage showing the letters:

What I particularly liked in this puzzle was the double-checking provided by the endgame – something one doesn’t always get from a numerical. With 58 of the 76 numbers in cells confirmed by the above letters it required only a minor bit of work to re-confirm the other 18. Using simple tests like 2 * 45 = 90, that sort of thing. I’ll look stupid now when it turns out I’ve made a mistake, won’t I!?

Cheers,

Tim / Encota