How strict are the the rules for creating art? Well, this is my take on all this.
The first rule is that there are no rules. Second rule is that there are only rules if you make them for yourself. Third rule is that art is not constrained to societies definition or standards. As humans, we want there to be strict rules because that would help us understand art more, but it is truly an untamed and powerful beast. Art is the result of experimentation. Even that is not a rule, because art can also be a traditional style passed down from generation to generation.
I find it quite creatively freeing to know there are no true rules. Although, society has imposed rules on art such as not copying other artist's work or creating fan art to sell, and yet those creations are still art. Just because you can not sell it legally does not stop it from being art. Art can be ugly, beautiful, angry, offensive, inspiring, emotional, painful, confusing, joyful, educational, product based, spiritual, evil, lovely, funny, dramatic, expected and unexpected.
We find it spray-painted on subway walls and on sides of train cars as well as framed on our walls. It is digital, photographic, sculpted, painted and drawn. Even the boundaries of art are hard to define. For instance, is something "craft" or "art". There must be strict rules because something can not be craft and art, right? Wrong. Art is creative expression. Someone can view something as art even though the creator sees it as craft. Art can be extremely complex or super simplistic. There are no boundaries.
If strict rules are imposed on art, art would break them. Art can not be constrained. I dare you to make your own rules. Just prepare yourself because art is unruly and will find a way to surprise you. Isn't that the beauty of art.