The obvious evidence of design in nature.
I like to think that I am an intelligent designer, and have looked at using genetic algorithms in my work so have some idea about the different approaches.
From reading other posts of yours - I *think* you are arguing for alien intervention rather than a supernatural intervention.
How was this achieved? Did they do it all at once and fake all the fossil evidence? Did they selectively breed over hundreds of millions of years - which would explain why organisms have the signatures of evolution because selective breeding is an a form of evolution with a very strong (artificial) selection pressure.
Anyway were all organisms designed or just some?
If humans were designed, then why put in the appendix? Why put in wisdom teeth?
If humans were designed, and these were minor errors that had been overlooked in the design phase, why were they not corrected as soon as the first hominid died from a burst appendix, or suffered from impacted wisdom teeth?
I make mistakes when designing something, but I then try to correct them when the testing finds them.
If all organisms were designed, then why the lack of originality? Why have horses and zebras using the same basic body plan? Why have housecats and tigers sharing such similarities, and why then have wolves and foxes that are more like each other than like felines, yet both obviously being mammals.
Why
design organisms that seem to fit into a "Tree of life"?
Why, given the lack of originality at that level, have so many different designs for the eye? Why put more than one design of eye on some animals
(e.g Notostraca).
If I design something, I tend to reuse components because it is simpler than redesigning it every time.
Why are there so many different plants that produce fruit? Why are there so many different parts of the flower that turn into fruit (either true-fruit, or false fruit)? This is easy to explain if they evolved separately, but hard if you posit a designer attempting different solutions, to the same problem.
Why design the eye in cephalopods so it lacks a blind spot, yet design it with a blind spot for mammals? If a competent designer is faced with a
problem (say blind spot in mammalian retina) and they already know the solution (no blind spot in the cephalopod retina) they tend to use it.
Why are vestigial organs vestigial, and neither fully working nor non-existent, which would look more elegant. For example either Basilosaurus, or modern whales have the more aesthetic rear leg "solution". Why did Basilosaurus have vestigial legs?