Triptic - both vertical paintings and one medium square painting
The Garden of Earthly Delights, by Bosch
Big square paintings
Café Terrace at Night - Van Gogh, Almond Blossoms - Van Gogh, Skull of a Skeleton with Burning Cigarette - Van Gogh
Medium square paintings
Sunflower series - Van Gogh, Irises - Van Gogh, Skull - Van Gogh
Small square and rectangular paintings
Square: Mona Lisa/La Gioconda - Leonardo da Vinci, Girl with a Pearl Earring - Vermeer, The Scream - Munch, The four seasons: Summer and Spring - Arcimboldo, Self-portrait - Van Gogh, Portrait of Dora Maar - Picasso.
Long horizontal painting
Wheat Field with Cypresses - Van Gogh