Software (nor any other creation/design) does not fall into a nested hierarchy. Especially if a god is doing the common designing, it's not at all necessary. But it is an inevitable result of evolution. Lo and behold, life falls into a nested (double-nested, even) hierarchy.Technically, yes, the evidence can point to a common designer. But ANY ARRANGEMENT OF LIFE AT ALL could point to a common designer. And yet we have the aforementioned nested hierarchy, an arrangement that is a necessary result of evolution.The fact that a "common designer" could explain anything isn't really even evidence at all, especially when the alternative is dependent on a very specific situation that matches what is observed.Say I have two chefs who want to cook a meal for me. The first, I tell him to make whatever he feels like. Anything at all. The second, I secretly tell that he must cook me an 11" thin-crust pizza with tomatoes, hot peppers, mushrooms, onions, and double cheese.My first meal comes. It is an 11" thin-crust pizza with tomatoes, hot peppers, mushrooms, onions, and double cheese. Based on the meal presented, which chef do you think prepared that meal, #1 or #2? Chef #1 certainly could have prepared it; he's capable of making a 11" thin-crust pizza with tomatoes, hot peppers, mushrooms, onions, and double cheese. He's capable of making anything at all! But the fact he's capable of making it doesn't mean he did, and can't really serve as evidence that he did. The fact that chef #2 had to make a 11" thin-crust pizza with tomatoes, hot peppers, mushrooms, onions, and double cheese and that's what I got is strong evidence that he was the chef that prepared the meal. Similarly, all relevant evidence (yes, all) is just what you'd expect if evolution were chef #2.