Infinitely descending scale on AY-3-8910

This is a discrete Shepard descending scale, a well known auditory illusion played by emulated AY-3-8910 chip (widely used in 80th 8-bit computers such as ZX Spectrum, Amstrad CPC, MSX, etc.). This chip had only three channels and 16 volume levels. It's seems to be enough to make an illusion of infinitely descending scale in mono.
It should play on real hardware too. It looks like this is first attempt to make Shepard scale in chiptune style.
What do you hear?

Видео Infinitely descending scale on AY-3-8910 канала ZX Spectrum Hotel