The Sky Simulated by White Flamingoes study for book, Concealing Coloration in the Animal Kingdom (ca.1905–1909)…
https://www.rawpixel.com/image/3235853/free-illustration-image-landscape-painting-vintage-sky-abbott-handerson-thayerFree Image from public domain license
Italianizing landscape by Michiel van Huysum (1744). Original from The Rijksmuseum. Digitally enhanced by rawpixel.