Minecraft wiki entry for Building_water_features, associated text: Another option to make your fountain bigger is to make the column in the middle bigger than one block. Consider using the center 3 x 3 area for the column. However, the frame must always be at least 4 blocks bigger in both length and width than the column. For example, if you had a 3 x 3 column, you must have at least a 7 x 7 frame. If you want a really giant fountain, make it with a 25 x 25 frame and a 3 x 3 column 25 blocks high.