The main issue is the synchronization. It needs to be sync that all LEDs work simultaneously when the Master sends a signal to the Slave saying the function that needs to be performed. I have not tried the other functions like 2 fade color, rainbow, etc. Because blinking is not working properly as it should. If you could try them out, please.
For example: when press '4' in the Tera terminal, it sends a message to each slave to do the function of right which in each slave is different. One does 14 LEDs blinking and the rest white on that string. In other strings will do half of the LEDs blinking and the other half of the string is white. And so on.
So all that blinking has to be in sync and every message send by the Master.
I am using a gpio interrupt to see if I could get it to sync but it didn't work. So, that could be taken out.