Here is how I make the stepping stones, Take a piece of plywood. Make your design (using a marker) you can make it look like a Dragon footprint or just a real stone (use your imagination, remember the bottom will be the top) take a piece of plastic and cover the whole piece of plywood. Next outline your design with finishing nails (no heads) about 2 1/2 inches long and spaced about 2" apart.. Once you have a good outline in nails cut cardboard into 2 1/2 to 3" strips, slide the corrugated cardboard over the nails so that the nails are in the middle of the card board. ( I like to use my husband's budwiser boxes cause they are slick.) You can use duck tape to connect the bottom of the cardboard to your plastic. On the outside, or it will change the appearance.
Mix your concrete ( I like the sand smooth finish stuff)
pour into your mold, let harden for days (if you are impatient make more than one). You should make them at least 2" thick or they will break. have fun.