While experimenting with visual effects in Rhythm Doctor, I found an interesting way to use visual effects that even I don't entirely understand. The effect produces a hazy, color-inverted backing for rows. However, there are actually two rows in two rooms used to make the effect.

Because of this, I came up with a use for them. Most of the time, the two rows would copy their movements and be indistinguishable. However, properties such as syncopation and row Xs won't always sync. There could also be unique sub-gimmicks between the shadows. And I haven't even thought about how oneshot rows would behave with the shadow…