If you’re a committed side sleeper, the Pillow Cube does the one thing it promises. That flat vertical side props your head at the right height so your neck stays straight instead of kinking down toward the mattress. We woke up with way less of that one-sided neck ache after a few nights. The shape that looks silly in photos is actually the whole trick.

It also keeps your bottom arm from getting trapped, since the cube edge gives your shoulder somewhere to tuck under. For pure side sleeping it nails the support.

Here’s the catch, and it’s a big one. The second you roll onto your back, this thing is awful. Your head gets shoved way too far forward because the loft is built for the side gap, not for lying flat. So if you switch positions during the night, you’ll fight it. It’s also firm and pricey for a foam block, and there’s a break in period plus a faint foam smell at first. This is a specialist pillow. Dedicated side sleepers might love it. Everyone else should pass.