This is how I make the garden stones that are so popular during the holiday season. I mixed up a couple of batches using plastic frames and stamps (e.g. Poetry Stones kit). I use the vinyl patch type of cement and mix according to directions. Filled each frame, smooth flat, and pressed in a few new phrases. When they were totally dried and cured, I painted on some watered down paint… filling in the letters.
When that coat was dry, I sponged on a contrasting color on the top and sides. These make nice gifts that last forever… inside or out.