In creating his "fungus accretion" vases, Simon brushed the rough surface of a ceramic vase with a clay-and-water solution until it built upon itself like a hand-dripped sand castle.

WSJ: The Wonder Twins of the Design World: Nikolai and Simon Haas | Designers

"Sunflowers" (1888 or 1889), from Philadelphia's own collection, is a virtuoso performance in color harmony, showing a ceramic vase of perky yellow blossoms against a swirling cerulean background, but it is entirely orthodox from a compositional standpoint, as the vase sits squarely in the middle distance at eye level.

WSJ: Vincent Van Gogh Up Close | Philadelphia Museum of Art | A Matter of Perspective | By Jonathan Lopez