I just finished reading da Vinci's biography by Walter Isaacson, which left me with a different sense of what it means to finish a piece of work. He famously never "finished" anything and eventually abandoned most of the projects he started.

He worked on the Mona Lisa for 16 years, adding a brush stroke here and there until his death, never handing it to the wool merchant who commissioned it or his wife who was the subject of the painting.

His work is largely a collection of drafts and anti-*'s, but that hasn't taken away from his transformative role in the history of art, science, and engineering. There is beauty in unfinished work and in what we abandon. Finality is not necessary for greatness.