used in different compartments the stuffing material 36 itself may also be different types as where one compartment is filled with polyester fiber and another is filled with foamed plastic particles these variations may result in a cushion 16 having pillows of uniform size as in fig5 or in a cushion 16 having pillows of different sizes as in fig6 in fig6 cushions of medium size 14a small size 14b and large size 14c are all contained within cavity 22 thus for example if the user wishes to sleep on his or her back and elevate the knees above the hips which is thought by some to be the least stressful position for the back a relatively large firm pillow 15a can be positioned below the knees among smaller pillows 15b as shown in fig1 this produces a non planar resting or support surface even when the mattress is positioned within a ordinary bed frame in fig5 and 6 the pillows are shown as loose or separate cells within the mattress but the same uniformity or variation in size can be achieved with integrally connected pillows sewn into a pillow bag 30 in yet another embodiment the pillows are separately formed but may be joined by attaching means 60 as shown in fig7 and 8 the attaching means consist of mating belts or flaps 62 and 64 sewn on adjoining portions of the loose pillows 14.