The sculpture is very impressive. Two of the 24 old testament elders play this instrument, one turns the crank, the other operates the levers.
The organistrum is an ideal instrument to give a solid fundamental pitch to chant or the performance of Spanish cantigas, but it isn't an instrument to play melodic lines. One string is tuned to a fundamental pitch, the other two a fifth above. When operating a keys all three strings are shortened. So it's not a drone instrument like a hurdy-gurdy or a bagpipe. It just provides open fifths as a sounding continuum for singers or other instruments.
I wanted to have an instrument just as beautiful as the stone sculpture and therefore asked my friend Elke Rutz if she would do the artistic carving and brought her together with Kurt Reichmann, one of the most experienced builders, who had done several versions of the Organistrum and had figured out what kind of mechanism works and which theory had to be out-ruled by practical experience. We settled on walnut for the wood and Elke did a wonderful job.