"The Sky" layer can be edited selecting its state from 6 marine art painting masterpieces of the 19th century:

Caspar David Friedrich - The Stages of Life (1834) Eugène Poittevin - Les Bains de Mer, Plage d’Etretat (1864) Gustave Courbet - The Wave (1869) Vincent van Gogh - View of the Sea at Scheveningen (1882) Paul Gauguin - Rocks and Sea (1886) Winslow Homer - Saco Bay (1896)

The owner of this layer is involved in the creative act by choosing the seascape's Sky.