Walmart.com has the 4-color cubes for $10.96 right now. I was just wondering--how big is the opening for the Whitmor grids? I tried counting the openings on one edge (9) and dividing that into the length of the side (14.75") and got 1.6" or so, which I know is too big. I realize, though, that my method didn't take into account the fact that the wires themselves have thickness, which would result in smaller openings than that--I just don't know how much smaller. Or am I making this a lot more complicated than it needs to be?