multiple images on same postcard

[penguin]

a recently purchased color post card ( early 1900s) shows the steps of
a mosque with people leaving the service, descending the steps. A
careful look shows that the postcard contains some persons in the
crowd appearing in an identical manner or in different color garbs,
but being the same person.
At the computer age I would not be surprised at this. Apparently they
were able to do it a hundred years ago.

Does anyone know of such a practice in the early 1900s?

Thank you,