Im betting its a limestone or similar rock that the softer rock bordering it has worn away and happens to look like a pattern. Just a guess of course but I feel confident. Ya know being the resident "I have a wierd rock guy" ......
"Bedrock river incision (downcutting) involves plucking rocks off channel beds, abrasion by fast-moving grains, and corrosion (dissolution). "
https://www.google.com/url?q=https:...9QEwBQ&usg=AFQjCNEMeoMjGFUkxrC6577TQ2nNWlXkyw
Im betting its a limestone or similar rock that the softer rock bordering it has worn away and happens to look like a pattern. Just a guess of course but I feel confident. Ya know being the resident "I have a wierd rock guy" ......
"Bedrock river incision (downcutting) involves plucking rocks off channel beds, abrasion by fast-moving grains, and corrosion (dissolution). "
https://www.google.com/url?q=https:...9QEwBQ&usg=AFQjCNEMeoMjGFUkxrC6577TQ2nNWlXkyw