nice idea, well executed. 64 and 1 could be swapped over though... (1 x 1 x 1 = 1, 1 x 1 = 1; 8 x 8 = 64; 4 x 4 x 4 = 64) so there is more than one solution to the puzzle.

all the squares are also fourth powers

But that's the joy of these grids, isn't it? Having red herrings and more than one solution makes it more of a challenge...

Nice grid
overlappy thingies are what makes the puzzles fun

Keener: well yes, red herrings are vital, but I think the key to a really good grid is only having one unique solution (but I admit it is exceptionally hard to be sure of that).

On Only Connect, the grids only ever have one unique solution.

Keener: well yes, red herrings are vital, but I think the key to a really good grid is only having one unique solution (but I admit it is exceptionally hard to be sure of that).

On Only Connect, the grids only ever have one unique solution.

Mr. qqq is correct, there should only be one solution. That does not exclude red-herrings, which are very important.

Or Ms. qqq, perhaps, apologies.

1,16,81,625 are all fourth powers (of 1,2,3,5)