I have 1 and 2/3 anti fatigue mats in my bed. They are made of a fairly soft thick rubber with holes. They are intended for commercial kitchens or workshops. The softness is nice when you kneel on them, and the holes let dirt, sand and debris drop through. They are 3'x3' as purchased, and I cut a foot off of one of them to fit my bed. They cost about $30 ea. from Home Depot or similar.