producing same u201d thus the description of the production method is omitted now in the left photograph of fig1 there are many random hills and valleys but heights of hills or depths of valleys are unclear the upper right zigzag line figure of fig1 clearly shows individual local distribution of heights and depths high hills sharply project at several points deep valleys abruptly pierce downward at more plentiful points mountains and holes are mostly isolated little linear grooves are found scarce mountain ranges exist the rugged surface has been made by lapping mechanical grinding it may be assumed that the mechanical grinding would make many linearly continual scratches but the fact is otherwise lapping makes many linear wounds in various directions by microscopic edges on the surface thus grooves are separated into individual isolated deep holes random direction cutting prevents continual grooves from surviving the same reason denies making continual mountain ranges mountains and valleys are asymmetric mountains are rather akin to quasi uniform valleys are deep and localized the down left figure of fig1 denotes a linear section cut along a line of y constant the dotted line is an average height line h 0 heights of mountains over the h 0 line are smaller depths of holes under the h 0 line are larger some of the holes have a depth of d u2212 0 35 u03bcm the rectangular part of 0 13 mm u00d7 0 10 mm of.