This painting by Ellsworth Kelly from 1966 consists of 4 panels of oil on canvas, and belongs to the collection of the Guggenheim museum (review coming soon), although I don’t think it’s currently on display because I don’t remember seeing it when I was there.
Note that Kelly had a reasoning behind his painting of solid colors, which is a composition he started experimenting with in the 1950s. For him, they represent the extracted essence of the objects he was painting. Instead of making a figurative representation, he broke things down to the most basic shapes and colors. These paintings also have a sculptural dimension to them because they have no figurative elements and therefore the focus is on their relationship to each other and to the space they are in.
The MFA has a similar composition (pictured below) from 1968 which actually inspired me to post about this one. In fact, you can see that the sculptural dimension is much more obvious in the second painting because the colors are not only arranged by their order in the spectrum but also by panel size.