The Black Swan is a slightly different version of the earlier Tarpan. It is a 3-string viola scale bowed instrument with a set of sympathetic strings. It could also be set up for the fingernail technique (like the sarangi). It is powered by two separate pickups: a rod piezo sitting under the bridge and a magnetic humbucker picking both sets of strings. The signals from the pickups is controlled with a blender potentiometer.
The Black Swan has another cool feature, it can be mounted on its wooden case which then doubles up as a sound box and be played acoustically.
Here's a video clip presenting a similar instrument, the Tarpan