Abstract: A device is provided for connecting two parts, of which one forms a recess and the other a counterpiece which can be pushed into the recess, and, to obtain a simple firm connection without the direction of insertion being fixed, there is on at least one part a coating which consists of granular rigid material and which is attached to a deformable, preferably elastic carrier material. The length of the granular elements is made greater than the distance between the opposing faces of the parts to be connected.

Abstract: One or the female part of two releasably connected parts has a recess, cavity or the like, the second or male part is a couterpart insertable therein. Engaging elements are formed by at least one layer of elastic, vertically extending bristles, short fibers or the like, which are preferably electrostatically flocculated and engage on an uneven counterface. The face or faces provided with elastic bristles or the like as well as the counterface or counterfaces extend parallel to the moving directions of the two parts. In a preferred embodiment, the uneven counterface is a second layer of elastic, vertically extending bristles, short fibers or the like. During displacement in one direction, the bristles are moved into inclined positions and have to follow every change of direction. Thereby, a resistance has to be overcome, the resistance reaching a maximum in a change of direction of 180.degree., i.e.

Abstract: A building element for the production of internal and external walls, parapets, fences, sheathings, and the like includes two flat boards joined by bars, and tongue elements. The dimensions of the elements are coordinated to permit many different ways of assemblage of the flat boards in order to form prefabricated building elements which are designed for specific purposes.