I guess the two 1 thing works... but I suspect some will see it and just assume a mistake. It needed more crossovers. Suspect people will either find this fiendish or straightforward.

"It needed more crossovers" was *not* the first thing that came to mind. All-number puzzles tend to be completely opaque to me, even if I am familiar with the groups; it's just too easy to find mathematical or referential patterns in an arbitrary group of four numbers.

Not a numbers guy but I managed to solve it, though I couldn't identify the blue group, which seems a bit cheap.

huh?

So are you saying there are 360 seconds in an hour? Think you missed a 0 off!! Would not have got it either way though