In 1965, the Museum of Modern Art (MoMA, NY) commissioned Robert Indiana to create a design for its annual Christmas card.  They chose Indiana’s red, green, and blue stacked letters of the word LOVE, which together have since become one of the most recognizable works of art in the world.   Although Indiana presented a number of different color combinations to MoMA, it was the museum who chose the palette for the card.   While other reasons have been posited, Indiana later explained the reasons he put the red, green, and blue together (which had nothing to do with the holidays):

 Most of my work is autobiographical in one way or another.  In the thirties, my father worked for Phillips 66, when Phillips 66 gasoline stations were red and green: the pumps, the uniforms, the oil cans… When I was a kid, my mother used to drive my father to work in Indianapolis and I would see, practically every day of my young life, a huge Phillips 66 sign. So it is the red and green of that sign against the blue Hoosier sky.  The blue in the LOVE is cerulean.  Therefore, my LOVE is a homage to my father.

Barbaralee Diamonstein, Inside New York’s Art World (New York: Rizzoli, 1979), at page 153.

LOVE paintings in various colors were featured in Indiana’s famed 1966 exhibit at New York’s Stable Gallery.  That exhibit also featured the first of Indiana’s Love Walls.

 In 1994 American Image Editions published ROBERT INDIANA: The Book of Love. The Book of Love consisted of twelve LOVE screenprints in different color combinations and twelve poems.  The tirage consisted of 200 “books” in Arabic numbers and an edition of 50 books in Roman numerals.  Proofs of each exist.  Each LOVE screenprint and screenprinted poem included in every portfolio was signed by the artist and numbered.