Spherical weathering in-situ
What you see is the bedrock consisting of sedimentary rocks (sandstone). On top it, is the man-made wall from basaltic rock bricks. What is special about this? The concentric layers, linear features and colours are produced by the weathering of the bedrock.
This sedimentary rock is made of volcanic rock fragments (sand sized grains) which break down into clay when exposed to weather (water and air). The linear and vertical feature is a joint, which allows surface water to infiltrate the bedrock and facilitate the weathering deeper underground.
The product is the weathering shells (yellow and orange concentric layers) that surround the corestone (purple rock, which remains largely unaffected).
You might notice small spheres protruding out of the right-hand side corestone. These are cannon-ball shaped features are called concretions. I invite you to “google search” these or look up my previous posts for more examples!
Photo taken in Wollongong Harbor, Australia.