Artists may produce work loosely categorized as visionary art for its luminous content and/or for its use of artistic techniques that call for the use of extended powers of perception in the viewer: (e.g. Gustave Moreau, Samuel Palmer, Jean Delville, Ernst Fuchs, the French Symbolist Odilon Redon, Brion Gysin, Max Ernst, Stanley Spencer, Edward Burne Jones, Adolf Wolfli, Fred Sandback, William Blake, Hieronymus Bosch, and Henry Darger).