3 piping bags fitted with 3 small round tips (Wilton #4)
Whisk together the confectioners' sugar and 3 tablespoons water in a small bowl.
Spoon 2 tablespoons of the royal icing into a piping fitted with a small round tip. Spoon another 2 tablespoons of the royal icing into a small bowl and mix in 2 drops of yellow food coloring; spoon into a pastry bag fitted with a small round tip. Add 5 to 6 drops of the black food coloring to the remaining royal icing; spoon into a pastry bag fitted with a small round tip.
Pipe 3 lines of black royal icing, side by side, on the top third of each macaron to form a belt. Let set, about 2 minutes.
Meanwhile, pipe 2 white dots about 1/4 inch apart below the middle of the belt. Put a silver candy button on each dot.
Once the black royal icing is dry on the surface, pipe a yellow rectangle about 1/2-by-1/4- inch on top of the belt to create the belt frame. Then pipe a line from the center of the yellow rectangle to 1/4-inch outside the rectangle for the belt fastener.