These cards are an example of a myriorama; a set of interchangable pieces depicting a landscape. Constant and repeated features in the foreground and/or the horizon support different pastural scenes in the middleground. From myriad, an indefinately great number, and 'entertainments' such as panoramas and dioramas, the holder of the cards is able to change around the pieces, creating their own landscape. The designer would start with one landscape, which would then be cut into 16, 24, or 36 individual slices.

Interactive myriorama at http://billdouglas.ex.ac.uk/eve/di/69238.htm