I didn't use a standard autotile pattern as the framework to design these tiles, although I think it's possible to arrive at this solution coming from that angle.
The core of this tile pattern for me is the line of the peaks running north to south (or north west to south east) that separates the lit and in-shadow areas of the mountain, and then working out from there.
I didn't invent this, though. I had done some studies of the mountains used in the Fire Emblem series some years back, so I knew this structure worked quite well from that.
As for rendering, I forget my exact inspirations, but I was going for a soft look with these. Three reasons: so characters can be placed on top of them and be easily readable (for SRPGs), help sell the scale, and because I liked it at the time.
This comment section is already very cluttered, so forgive me if I don't go into details for rendering tips.