Hello Mara, The stamp could simply be put on upside down by accident, but the following is also possible. The position of a stamp in a certain way was sometimes used as a secret kind of language/message. Most often used between secret lovers. Upside down could mean: I love you, sideways could mean kisses. or tilted could mean I think of you. In the Netherlands it is known as Postzegeltaal. Roughly translated Stamp language. There are even postcards with Stamp Language. Kind regards, Johan.
