The chime forest consists of 18 glass vases. Each vase has an electric motor suspended above it that can be raised and lowered. The motors have various things attached to the ends that throw the rotation off balance and make the motors jiggle. When the motors are lowered, they collide with the vases, making a tone. Since the motors are unbalanced, they bounce off the vases and then collide again, creating a fairly regular but unpredictable rhythm.
The vases can be tuned by adding water to the inside; adding water lowers the pitch of the vase. Each vase can be tuned about an octave, so the instrument can be tuned to any desired scale. For this posting I've left out the water, since the vases already cover a pretty wide range of notes:
The only additional control is an on/off switch. This switch activates or deactivates the motors. The instrument can still be played even while the motors are off, but it won't have quite the same sustained rhythmic effect. One use of this switch is to pre-set the motors up or down, so that turning on the motors will activate a specific "chord", and turning it of will stop it.
Since the chime forest is a fairly large instrument, it has been designed for easy assembly and disassembly. The wooden frame can be assembled with no tools. The wiring still requires a screwdriver to attach, but a future revision might be to add plugs in place of the screw terminals.
Here is an example video showing the chime forest in action:
