How to calculate the names of hundreds of families by measuring the palms in the street?

There is a similar method in the street. There are hundreds of surnames (divided into several groups) on the ground. Hundreds of surnames are written in groups on a pile of cards, and then the cards with their surnames are put on the ground in groups to let the scammers know your surnames. Actually, you told him that.

It is estimated that the palm of your hand is similar, inadvertently revealing your last name.