Hello, GGPaltrow!

Find all such pairs of positive integers ,

for which a rectangle with dimensions can be built

from pieces created from 6 squares as shown.

(Note that you can both rotate and flip the pieces):

. .

OK, so we know that we can create a 3x4 rectangle

. . by simply putting together this shape and the one rotated by

. .

We can also create rectangles for positive integers and

But what else? .I'm kind of clueless ...

Me too . . .

I've tried to find other possible rectangles, but have failed so far.