Abstract: Method for folding plane surfaces wherein, given a plane surface on which there are identified a pluratity of alternative primary folding lines and, parallel to each other and capable to generate a wavy structure, each primary folding line is linked to the subsequent primary folding line by means of two further secondary folding lines, having same origin on the folding line and diverging between them them with angles .beta. and .GAMMA. with respect to the perpendicular to the lines, being 0.ltoreq..beta.<90.degree. and .beta.<.GAMMA.<90.degree., said joining being performed at least once, then two additional secondary folding lines, corresponding to the previous and, being traced, specular with respect to a simmetry plane passing through the said primary folding line.