bake the bricks in bread pans along with the cupcakes(in muffin pans) acording to the instructions that come with the cake mix
place the large marshmellows on the cake with icing. You need to have six marshmellows(three on a row on each side of the cake) on one cake and four marshmellows(two on each side)on one half of the remaining two cakes.
mix icing with fun colors and apply to the cake stack the cake with the most marshmellows onto the sides of the other two cakes that have none.
ice cupcakes with white icing and add the lego gummies ontop