Artists tend to use the medium most available to them. As buffalo hides became scarce in the late 19th Century, Plains tribes resorted to drawing on the next-most abundant material: paper from accounting books. Artists drew pictographs of important events sometimes overtop lined paper and hand-written debits and credits of a local business. The style became known as ledger art. Now, a new generation of ledger artists are reviving the art form. Notable examples of ledger art are part of a new exhibition at the Smithsonian National Museum of the American Indian.