We have a foreign company, the bosses are Chinese. One (little) onCalnik returned from Xerox, where he made a copy of some document for his (large) onCalnik. And he began to combine, several times, the original and a copy, placing a mark next to each letter and number - first from the top, then from the bottom. I asked him "Why are you doing this? There can be no difference." He replied, "I believe only my eyes".