What an awesome work! This is a great way to add an artistic element to your floor or garden. And of course, you don’t have to follow this pattern. You can design any pattern that you like.
The work is relatively straightforward, but it does take quite a bit of planning and work. Check out more detailed instructions at this stone art blog in the following link.
Later I also found that there was a short cut. There are commercialized stepping stone kits available in the market. The following picture is an example I found on Amazon. As indicated by the name, the kit includes all you need to make a stepping stone. I like the idea as it make your life a lot easier. Check out what customers say about them at Amazon in the following link.