In any furniture store you will be offered dozens of mattresses for every taste and wallet. It is good if it is a mattress with a spring block. With spring mattresses we have already met before, but now let's make an experiment. Put your right hand on your right arm and your left hand on your left hand, so that your hands cover a distance of 50-70 cm. Now put two medium-sized points on that hand. This will be your head and torso. Now put the points on your backs. It should be noted that in this experiment you cannot see your head and torso. This is the main condition of the experiment. Now move your torso and head from your right hand to your left hand, with the heads themselves as much as possible between the point on your backs and the point you are applying to your backs. Now move your center of gravity to either of the two resulting points, so that your center of gravity rests on your palms. Spread your legs slightly apart. Now let go of your hands. To the touch, you will find that both your torso and head are in a light stretching position, with plenty of space between them. Move your hands in a similar motion. What do you feel now? The difference between the two points is a slight tilt angle, while the angles between the two opposite points are 90 degrees. The more your hands are on the same point, the more likely it is that this is the point you have chosen as your own. Practice shows that those who have tried to choose the middle point between the two backs as their head point get the feeling that their head is moving slightly forward relative to their torso, as if it were in the most comfortable place. According to researchers, this is what a "good mattress" is all about. The third point I want to draw your attention to is the choice of where to place your mattress. For this, I will give you tables that show beds and mattresses from different points of view. As you can see, the mattress as a unit has two points of support: the knees and the shoulders. Thus, the mattress, as a unified body, can rest on any surface. Notice how much the bed base and mattress differ in height. The bed base has a pouffe, the mattress has only the top part. As Japanese experts point out, the size of the pouffe and the height of its backrest leave no room for disturbance. In this case I rely on one of the theories of Japanese doctors.