The Great Intelligent Design Challenge

Some months ago, I made a challenge to an ID group. The key to ID (aside from being able to point to an actual designer) is the ability to unerringly determine if something has, in fact, been designed. A typical ID argument is that if you are walking in the woods and find a watch, you would assume the watch had been designed and manufactured rather than having grown on a watch tree and fallen to the ground. But the argument is never about finding a paleolithic tribe living in a cave facing the direction of the equator with a sundial at the entrance. You observe that the tribe uses the sundial to organize their days -- it has utility, it tells the time. Just like a watch. But you would never know if the gnomon was a stalagmite that happened to form near some regularly spaced markings or if someone designed it. You never hear that example because that’s the point where ID breaks down.
So I presented three items and asked the good folks to run them through an algorithm and decided whether each was designed or just happened by chance. Item one was Hexagon Pool Park in northern Israel. It’s a big basalt outcropping of various heights damming a body of water behind it. Basalt outcrops in regular hexagonal columns with flat (i.e. parallel to the ground, at right angles to the altitude of the columns) tops. The water behind the outcropping has worn a course through the columns and filled a “lake” at the bottom. The watercourse has worn the basalt smooth. What you have is a park with a waterslide, a swimming pool, steps to get up to the top of the water slide (the tops of alternating basalt columns), picnic tables (again, column tops) and chairs (column tops below the top of the column you choose for a table). All that had to be added to this was a visitor center, an outhouse, and a falafel stand and they were in business.
Item two was doggy football. This is a phenomenon in urban dog parks, where there are always a fair number of dogs. One dog will grab something, a stick or a ripped tennis ball typically, put it in his mouth and start walking around with it until the other dogs start following him around and then a bigger dog will challenge him for the thing. Some other dogs will defend the challenge, and some dogs will back the challenger. The challenge is almost never successful. But then at some point, the dogs will all retreat from the dog with the thing, and then that dog will drop the thing but keep it between his paws. And then another dog will try to grab it and a new round begins. This is a game with very well-defined rules and it pops up in almost any dog park with enough dogs.
Item three was a rock I found on a beach on Cape Cod. I’m uploading a picture. I “know” the designed/natural answers to the first two items but have no clue about item three. The rock seems to have a picture of an animal on each side, or it could have bunker oil tar markings embedded into the water-eroded rock.
So basically, what I got was some gibberish about complexity and something called “Shannon Information.” And of course, no step-wise test to spit out an answer.