Imagine that you and six of your friends are in a pitch-dark room and feeling different
areas of an elephant. You can't see the elephant, so you all think it's something different.
If you're touching the tusk, you think the elephant's a hard, pointy thing; if you're
touching the ear, you believe it's floppy.
Now, put the universe in place of the elephant. People understand some parts of the
universe but not how all those parts work together.
Einstein spent the second part of his life trying to develop a "complete theory" that
would explain all the forces and phenomena in the entire universe. He never finished it.
Many believe that Einstein spent the last part of his life "spinning his wheels" working on
this theory. Today, scientists see value in Einstein's idea and are still trying to come up
with a "theory of everything."