That's the kind of thing I was referring to earlier.
Panels report left & up, for instance, on who is to their right or below, based on those panels pullling an input pin low.
The micros on the panels then negotiate where they are, all streams go to all panels, the micros pick off the data intended for their LEDs.
Wouldn't it be better to have the master send each uController its specific data, as opposed to flooding the whole matrix? If I can identify each uController by address (hence the i2C possibility), I can also send each one specific instructions and I don't have to flood the whole thing. This also allows me to send instructions to just one panel, and the rest can simply repeat their last instruction received. This would cut down on the data being transmitted across the whole thing, no?
I know there are ways to add a star topology to I2C, there are ICs specifically for that. I just have to figure out if they would work in this scenario without adding too much overhead, or wasted resources, while also keeping everything identical for manufacturing purposes.