Algodoo

Entropy means that everything in the universe will eventually fall into a state of disorder. It never happens in reverse. For example, when you place an aspirin tablet into a glass of water, the tablet will dissolve until it no longer resembles an aspirin tablet. The process can never reverse where a cloudy mix of chemicals in a glass of water spontaneously solidifies and assembles itself into a perfectly formed aspirin tablet. The arrow of time only goes in one direction (or DOES it?! )

Press Play and watch entropy repeatedly reverse itself!