Just put together this video the other day, leaning heavily on Castle modules (especially Counter and Multi-Gate, but also Flips Flops and ADC).
Though of course this is just the tip of the iceberg as far as what they can do. Wanted to keep this relatively simple, monochrome, rectilinear. I think sometimes the challenge is not to overcomplicate things.
+++ Should note, I guess, since the whole thing is composed of audiovisualization via Sensory Translator, that this is not recommended for those with photosensitivity as there is quite a bit of flashing.