It refuses to be controlled. Therefore Life is by definition impossible to rigidly define. We are unable to completely capture organisms with our concepts. We can never be sure that Life will be the same tomorrow as it is today. Life has the extraordinary ability of making its own definition obsolete.
Complex systems have the ability of designing themselves.
To watch a system self-organize is always fun and fascinating. And paper clips are so simple and handy that anyone can play with them. In order to make a simple Complex system you need to do the following. Open the paper clips half way up so that they are easily able to hook up to each other. Put all the disconnected paper clips in a jar.