I’m always forgetting to shut the door. So I made this door shutter. My machine is 8 steps long. At step A, a pulley pulls a lever that rolls a ball into a basket. The basket is step B which drops with the ball and hits another ball that rolls along an incline plane, which is step C. At step D, the ball hits a nail, that pops a balloon that gives way to another incline plane at step E. A ball rolls down the incline plane and knocks a block off its stand. At step F the block falls onto a clothespin causing it to open and release a string. At step G a spring punches into a door that closes, step H. That is how my door shutter works. Now here is some more information to learn about my automatic door shutter. My first step A is a pulley. It is a pull force. B is a gear. It is a gravity force. C is an incline plane. It is a gravity force. D doesn’t have a simple machine in it. Friction is the science concept. E is an incline plane. The science concept is a push but I will substitute this phrase: "an incline plane is a ramp that is a simple machine". F’s science concept is a substitution that says this works because levers lift loads with less effort. Of course the simple machine is as said a lever. G is a spring. It is the only spring in my machine. The science concept is a push force. H doesn’t have a simple machine but its science concept is again a push force. So these are the steps of my simple machine.