Suppose you found an acorn. Would you say, "Look at this amazing artifact! Someone must have made it!" No, you wouldn't, because acorns grow on trees. They are part of nature, just as rocks are part of nature. Didn't God make rocks?
You’re free to join the experiment if you like.
If I had never seen an acorn or a tree I don’t know what I’d say. And one must not confuse design with origin as the question about God making rocks does.