Created: October 20th, 2015
Wow, this is pretty neat. A great take on the Muller Lyer illusion. The combination with the Shepard Tone really helps it. It looks kind of like an ascending ladder. It would be kind of cool to have some kind of object "moving" on top of it, perpetually sliding down the stairs.
I noticed that you said it was difficult for you to create a Shepard Tone from scratch. I don't doubt this, but there are several resources online which can create one for you without you having to cut up Youtube video soundtracks. This thread has a Shepard Tone plugin for Audacity, a free audio editor. You would also probably be able to customize the tone's speed to match your animation.
I think the only problem really with the end product is that it's not quite a perfect loop. Although the initial part was cool, it does prevent it from being a loopable gif/video. Maybe if you had an ending with the bars sliding all the way across the screen, or forwent the initial climb?