The J.C. Leyendecker painting “George Washington at Valley Forge” inspired the 13-cent multicolored Washington at Valley Forge stamp (Scott 1729). The painting first appeared on the cover of the Saturday Evening Post on February 23, 1935.
Printed on the Combination press, or A press (702), using plates of 460 subjects (twenty across and twenty-three down), the stamps were tagged, perforated 11, and distributed in panes of one hundred.
The sheet contains five 'floating' plate numbers that move up and down the left or right vertical margin. There are twenty-three different positions of the plate numbers on each side.
Scott 2005 Specialized Catalogue of U.S. Stamps and Covers
Durland Standard Plate Number Catalog, 2005