
But for a more serious note.

Stamp upside down in the left corner - I love you
Stamp crosswise in the left corner - My heart is another's
Stamp straight up and down in the left corner - Goodbye sweetheart
Stamp upside down in the right corner - Write no more!
Stamp in the middle at the top - Yes!
Stamp in the middle at the bottom - No!
Stamp diagonally across the right-hand corner - Do you love me?
Stamp diagonally across the left-hand corner - I hate you
Stamp in the top corner at the right - I wish your friendship