Convoluted egg-crate polyfoam is a classic and versatile bed topper solution. When the cones are placed upward, they provide additional contour that acts like a pillowtop, softening a too-firm bed. Lying on the smooth surface, with the cones down, provides a more supportive structure that adds additonal padding and comfort to a worn mattress. The foam stays in place and performs well under a mattress pad or fitted sheet.