Suppose you carved hardened grooves down a set of wooden ramps and you let a ball roll down the path defined by those hardened grooves.
This contraption is a "machine" of sorts. It has a moving part, the ball. It has a useful purpose: entertainment and education about the laws of physics.Assuming there is no prior art, few would question whether such a "machine" and its "method" of use are patentable subject matter under 35 USC 101.
It should be "obvious" where I'm next going with this.
We are going to make the path that the ball follows less fixed, less hard. For example we can put a number of spring-closed trap door holes at spots along the upper and middle ramps. We can let the child use a set of strings connected to the trap doors (the monostable unlatching means) to determine ahead of time or dynamically in real time which trap doors pop open and which remain closed at least until after the rolling ball has passed that position.
The contraption is still a "machine", albeit a slightly more complex one. The ball still follows the laws of physics and moves towards the point of least energy. However, this time the path is defined in a "soft" way depending on how our innocent child pulls the strings.
What we have now is a tangible machine in combination with a pattern of dynamically changing or fixed energy states. The energy states are those of the monostable unlatching means, the spring-closed trap doors.
Consider next a machine whose moving balls are constituted by electrons, whose hardwood grooves are constituted by fixed wirings, and whose spring loaded trap doors are constituted by latch driven AND gates. What's the difference?