These pieces are each 4 x 4" on archival mat board. They are done is acrylic paint and colored pencil. They are sold as sets of three based on color.
One of the hardest things for me to do in my work is to have a limited amount of marks on a piece in order to imply a lot with minimal lines. I started out with this goal in mind, but found myself adding colored pencil marks at the end to contrast the paint color and create more texture.
Since these pieces are sold as sets, I think that if they were framed individually there are a lot of options. A few thoughts would be to scatter them in a bookcase or put them along a wall a bathroom. You can read more about where to put small pieces here.