In the drawings: Fig. l is a plan on an enlarged scale of a netlike web or fabric constructed of threads and which typies one element of several forms of products according to the invention, certain proportions being exaggerated to facilitate illustration; Fig. 2 is a fragmentary perspective of a component of the web represented in Fig. l; Fig. 3 is a cross-section on the line 3--3 of Fig. 1; Fig.