Simple-Circle-Button.md

@@ -99,6 +99,9 @@ for (int i = 0; i < bmb.getPiecePlaceEnum().pieceNumber(); i++) {
             // The color of boom-button when it is at unable-state.
             .unableColor(Color.BLACK)
 
+            // The color of boom-button when it is just a piece.
+            .pieceColor(Color.WHITE)
+
             // Whether the boom-button is unable, default value is false.
             .unable(false)