Ferrofluid sculpt with Interactive Base or Wall of Ferro-Pixels

What if I have the fluid in an ‘outside’ container, like an oil and vinegar combo cruet. I was thinking maybe also just a bunch of tiny glass containers filled only halfway. Basically the glass with the ferrofluid obscures something else — something behind it or inside [so behind 4 sides, like if in the cruet]. And you use a magnetic item (wand, ring, or a _drapery_ of some sort would be cool) to move the ferrofluid — in order to reveal what’s behind.

I purchased a set of tiny glass spheres [meant for necklaces] for under $10 online and created a ferro-pixel wall with a piece to be revealed behind it. Unfortunately, I am not able to justify the rather pricey purchase to acquire enough ferrofluid to fill more than a few, but the effect and interaction is cool.