I owned a glazing contracting corporation - essentially a Glass Company. I sold sole interest in it and retired last September. I think was at that particular customer's home on behalf of a general contractor - to review the customer's needs for one or more of the many facets of the glass trade. I just happened to look down at the stone mulch already in place, and that particular stone just sort of jumped out at me, figuratively, of course.
In the 80s, I was at a Chicago hotel on business and happened to note there was a bonsai show being set up. I was so enthralled with the diminutive trees I decided I HAD to know how to do it myself. My growing abilities and understanding of how plants work is entirely a byproduct of my continuing pursuit of greater proficiency in the art/science of bonsai. I've found the single most important key to success for any container growing ventures is knowing how water behaves in container substrates and how to harness the concept. Initially I failed at bonsai, but putting the trees aside and delving into soil science brought salvation and is really what's buoyed my endeavors these last 35 years. That's likely more than you wanted to know, but I do enjoy talking and sharing thoughts with other gardeners.
Al