background BART ceramic hexagon honeycomb San Francisco subway surface texture tile tiles Underground urban wall abstract art-glass blended blocks brown clear coloration colored coloured contrast crafted decorated decorative distinctive embedded glass hexagonal hexagons interconnected interlinked kaleidoscopic light mosaic multicolored multicoloured paneling panelling panes patterned patterns perspectives presentation raised rounded shaped shapes stained-glass style surfaces surfacing symmetrical tactile textures variations variety wallpaper window bugs cells chambers creepy crawly insects nest occupied paper wasp unoccupied wasp celebrate celebration defocused design festive glamour glow graphic illustration lights party purple shiny alien black blue burst creation floral flower futuristic gold metallic outer space space spikes star accident danger fall hill hillside lichen mesh metal net netting pattern prevent rock rockfall safety secure wire bee beehive beeswax cell clos food golden healthcare healthy honey honeyed macro medicine nature pollen