This is a fun motion graphics animation I made in Cinema4D.
I used a MoText object as a container, with a clear perspex material applied with a refractive index near to 1. Each letter then had a particle emittor added, angled appropriately. Each emitter was told to use multocoloured spheres as partciles, with the generational timeframe set to just fill the casing and no more. The volume of the letter decided this timing (an interesting way to get a feel for how letters differ in "weight" in general 2D typography!). A dark reflective floor gives added movement and interest.
Looping was done in Adobe After Effects.