Make a recipe of royal icing.  Thin-down the recipe with warm water.  (To test the recipe for correct consistency, let a drop of thinned-down royal icing drop from a spoon and into the royal icing that is in the bowl.  If the droplet disappears at the count of 9-10, the royal icing is of the correct consistency).  Tape the pattern to the work surface (table).  Place a piece of waxed paper over the pattern (drawing).  Tape the waxed paper to the work surface (table).  Trace with entire pattern using regular-strength royal icing and the color(s) of your choice.  Let dry.  Fill in each section with thinned-down, royal icing with the colors of your choice.  Let each color and section that is touching another dry before filling in another touching section.  Let dry.  Use a non-toxic, felt-tipped pen for features and adding character to the design.  Remove from waxed paper when thoroughly dry and place on the cake.