Abstract: A multilayer material is disclosed which consists of polyethylene foam sandwiched between two external layers of high-density polyethylene. A two-step manufacturing process for forming such a multilayer material is disclosed, which consists of (1) thermal bonding of a roll stock of PE foam with a roll stock of HDPE/LDPE laminate, followed by cutting into composites, and (2) thermal bonding of two composites to form a multilayer material.

Abstract: The present invention relates to construction assemblies or modules. There are attachment members that are connected by pressing an elastic protrusion head through an aperture and threading the protrusion head from one side of the aperture to the other. As the area of the aperture is smaller than area of front projection plane of the protrusion head, threading the protrusion head into the aperture requires the deformation of the protrusion head. After traversing the aperture, the protrusion head returns to its non-deformated shape, and the protrusion neck is settled within the aperture.

Abstract: An exercise device comprising a first foam layer and a second foam layer; wherein the first foam layer has a thickness of between 10% and 35% of the thickness of the exercise device, a Shore 00 value of between 60 and 85; and a compression deflection at 25% of from 100 to 145 kiloPascal; and the second foam layer has a thickness of between 65% and 90% of the height of the exercise device; a Shore 00 value of between 35 and 65; and a compression deflection at 25% between 20 and 75 kiloPascal. The exercise device may further comprise a third foam layer; the third foam layer may have a convex external horizontal side. According to some embodiments, the third foam layer may be detachable affixed to the exercise device. A method for using the exercise device is also disclosed.