Coralstone Block

Placed coralstone sprouts coral growths across its face, so one tile already looks busy in a way most decorative blocks do not. The thing to know before you build is the merge behavior. Fill a solid square at least three tiles on a side and the middle stops drawing coral and switches to a fixed sponge pattern instead, the same quirk sunplate has. Thin runs, single accents and outlines keep the coral. Broad flat walls do not. Pick which look you are after before you commit to a shape, because the swap happens on its own once the area gets big enough and you cannot turn it off.