Design is so obvious that even an unusual stone is enough to infer it. Even the most ardent Evolutionist will pick up on the design that went into a hand axe, for example. While relatively simple, the hand axe is so obviously designed that its purpose has been studied and debated since its discovery (and it turns out, it may actually be a hunting weapon, not an axe). Even the most ardent Evolutionist knows it was designed.
In nature, there are many clear signs of design. In fact, the designs found in nature are so incredible that humans often try to copy them. Sometimes, as is the case for gears in planthoppers, we even find that designs we've been using for years were being used by God for much much longer.
If we cannot deny the obvious design in stone tools, we cannot logically deny the obvious design in nature. It would make more sense to go the other way, claiming that our designs are so pitiful, they must be the products of nature. Evolution, or other forms of atheism, just aren't options God has left open for us. If you want to deny there is a God, that's entirely your choice, but you must commit intellectual suicide in order to do so.