Is a piece of art ever truly finished?

How do you know when a piece of artwork is truly done?

I doodle at times. I find it therapeutic in that I can let my mind wander while my hand draws. I start out with a random line here or there and keep working at it. Soon the paper, envelope, whatever I'm doodling on ends up this elaborate, weird design. I put it to the side and sometimes days, months later I pick it up and doodle again. They usually turn into these complex images that, according to others who've seen or looked at them, form different things based on the way you look at them. It's a quirk of mine.

I started these elaborate doodles several years ago when I'd find myself sitting and trying to find a muse for a story I was writing and failing at completely. Writer's block, in essence, turned into designing these weird ink pictures. I've thought of sharing them online but only ever shared one envelope and scanned several others. I've had people I work with tell me that they're neat but sad. Why? Because I draw them on lined paper and not plain paper. What?

I still, to this day, doodle on lined paper. Some day I plan to do them on plain paper. I don't add color, but I've been thinking about it. Guess I could coin these weird doodles as therapeutic drawing?

I don't know, whatever it is I do it off and on and always, always when I go back to glance at them months or years later I'm surprised at how interesting they look.

** The above picture was drawn by hand by me **