Made for my son's 5th birthday party. Gotham city was made with fondant mixed with gum-tex, cut out, then hardened for 3 days. The black was Satin Ice which hardened up quickly like gumpaste but the gray buildings were MMF which in four days still where not nearly as stiff. The cakes were WASC with buttercream, yellow with chocolate buttercream, and chocolate with chocolate buttercream.