Unfinshed paintings

4 ) Some of Leonardos paintings remain unfinished. Why?

Leonardo's interests were so broad, and he was so often compelled by new subjects, that he usually failed to finish what he started. This lack of "stick-to-it-ness" resulted in his completing only about six works in these 17 years, including "The Last Supper" and "The Virgin on the Rocks," and he left dozens of paintings and projects unfinished or unrealized.

He spent most of his time studying science, either by going out into nature and observing things or by locking himself away in his workshop cutting up bodies or pondering universal truths.