Higher on the sides II

Picture a bed of nails, densely packed. Now blunt the ends of the nails and add atop each nail a 10 centimeter-long dense cushion. Make each cushion wide enough to touch the one beside it. Surround this mechanism with a wooden frame such that the cushions cannot be pressed outward. Under each nail add a simple, robust, independent lifting mechanism capable of pushing it upward by about 15 centimeters. Under each lift add a powering mechanism controlled by a central computer.

Got all that? Okay. Now use automated line tracing to teach the computer where your hips, shoulders, arms, feet, chest, and head are. Use the program thus created to move the cushions such that no matter how you turn or move the pins in the bed will automatically adjust to keep your spine perfectly straight but make room for your arms, hips, and whatever else juts out of your body.