Photo Term Series Post #4: Diptych/Triptych

For this term I’ll quote Merriam-Webster’s definition:

Diptych

1 : a 2-leaved hinged tablet folding together to protect writing on its waxed surfaces
2 : a picture or series of pictures (as an altarpiece) painted or carved on two hinged tablets
3 : a work made up of two matching parts

A Triptych would be the same, but with three matching or related parts.