Nothing quite visualises the flow of time so distinctly as the flow of sand through an hourglass.
The sand flow, or flux if you will, proceeds at one second per second under the temporally uniform force of gravity.
The Hand-Cranked Flux Capacitor is a mechanical time machine, a contraption that puts the flow of time in your hands.
Here's how it works:
The sand timer is mounted in a vertical-axis centrifuge which is spun by the hand crank. Around the periphery, a thin cylinder with viewing slits rotates in step, meaning the stroboscopic effect, much like a zoetrope, allows the spinning sand timer to be observed as if static.
The faster the handle is turned, the faster time flows.
The timer itself is held by an arm with a mechanical linkage that is able to flip the timer end-to-end. This motion is controlled by the direction of rotation. If the crank is turned clockwise, the timer is in one position, anticlockwise and it's the other position. Conversely, the viewing screen always rotates in the same direction regardless of crank direction.
The overall effect is that winding forwards allows the sand to flow normally, with the zoetrope effect freezing the motion of the timer in its position nearest the viewer. Turning the crank backwards surreptitiously flips the timer and the zoetrope effect freezes its motion at the far end of the centrifuge, appearing "upside down" to the viewer, simulating the reversal of time.
It doesn't really make much of a statement as an art piece, but I think it would make a fun toy.