The following argument is valid:
- Many butterflies are works of art.
- If God does not exist, then no butterfly is a work of art.
- So, God exists.
Note that with the progress of genetic engineering, we may have to modify (2) to "If God does not exist, then no butterfly that isn't genetically engineered is a work of art" and then strengthen (1) to say that many non-engineered butterflies are works of art.
The thought behind (1) is not just that butterflies are beautiful, but that the best way to appreciate their aesthetic qualities is to see them as works of art.