The reason why sushi is served with 2 pieces

Why is sushi normally served with 2 pieces?
The following is one of the reasons.

In the beginning of 19th centuries, sushi was started to be enjoyed as a fast food on the streets.

People used to eat sushi while standing at the unsteady counter so 1 piece of sushi easily fell down.
That’s why sushi started to be served with 2 pieces to support each other.