I heard these sorts of designs could have been used for fishing, or other types of hunting / farming. Basically the fish are herded and funneled into some patt

I heard these sorts of designs could have been used for fishing, or other types of hunting / farming. Basically the fish are herded and funneled into some pattern where they are caught, maybe when the tide recedes or when they enter a choke point. Or maybe it's irrigation channels that somehow got cooked into the landscape permanently. Thar desert is relatively flat, and close to the coast and rivers, so it's not inconceivable that it could have born more water in the past.