Beauty: an optional extra
There are many examples among living creatures which exhibit symmetrical patterns, interesting colour combinations and textures, and a rich variety of forms based on a common theme such as butterfly wings. Often this beauty does not appear to provide any special advantage to these creatures compared to plainer versions. In other words, the beauty simply adds to our appreciation of the creation.
Beauty is not a selection criterion for a blind process such as evolution, because it does not confer a benefit to the system. However, beauty is something that a benevolent designer might choose as an add-on to an artifact or a created system.
Many scientists insist that the elaborate ornamentation and behaviour patterns in male birds of paradise and peacocks, for example, came about through sexual selection. Actually, the scientists are at a loss to explain why these birds are so beautiful. They therefore suggest that the females of the species all had the same unique picture of beauty in their heads so that they all consistently selected for the same features. That would only work if the females were programmed with the same ideal of beauty. But then what, or rather who, put the picture of the ideal into the female heads in the first place? It is impossible to escape the need for a designer.