r patterns of surface elements at least some of which are elongated, the pattern of one surface area being displaced in relation to that of the other surface area. 3 Claims, 7 Drawing Figures PATENTED i SHEET 1 m: 3 PATENTEU W128 I975 SHEET 2 BF 3 DR/V/NG LICENSE FOR DOCIUIVIIENTS VERIFIABILE AS TO THEIR AUTHENTICITY Great efforts have been spent in making documents such as banknotes, identity car