This instrument has short lengths of hardened-steel threaded rods attached at right angles near the ends of spring-steel tines. They’re played by percussion with hard or soft beaters. These assemblies have various modes of vibration producing multiple frequencies, and by striking in different ways you can bring out the different tones. Much of the effort in making the instrument goes into adjusting the relative lengths of the rods and tines. You don’t go into this intending to tune to tune to a particular scale, because the interacting modes are not very amenable to being told what to do. Instead, it’s an exploratory process, looking for whatever tonal relationships you may be able to coax out of it that are appealing to the ear.