Bake and cool 1-layer sheet cake, 1 1/4 in. high. Cut into 2 in. squares using knife. Prepare cakes for poured fondant by icing lightly with buttercream. Divide poured fondant into 5 portions; tint rose, blue, peach, violet and yellow. Cover cakes with poured fondant; let set.
Tint 5 portions of fondant slightly darker than poured fondant shades. Roll out 1/8 in. thick. Cut a heart to match each cake color using smallest cutter from set. Position on cakes. Pipe tip 3 dots in buttercream.
*Combine Violet with a little Rose for violet shown.