I had never attempted a triptych before, but was always fascinated by their narrative potential—like large comic book panels created in oil paints. They tell a story and/or aesthetically work together. Sometimes the "panels" have a particular hierarchy, with the middle panel dwarfing the other two. This is evident in work produced by many painters during the northern Renaissance:
The Crucifixion Triptych by Rogier van der Weyden
The triptych became a great vehicle for Biblical narrative (sometimes paired with extra-Biblical narrative). Triptychs were so large they had a permanent position in churches or were created as portable reminders of Christ's sacrifice. Hinges could be added between the panels and the paintings could sit on flat surfaces, much like modern-day picture frames.
Hieronymus Bosch's famous The Garden of Earthly Delights shows a highly fantastical interpretation of the human story including an account of Creation, human thriving and damnation.
Actors by Max Beckmann
Francis Bacon used the triptych to create iterations of his nightmarish portraits:
Three Studies of Lucien Freud by Francis Bacon
Someday, I hope to experiment more with this style of visual storytelling ...maybe when I finish my thesis.