Hi egvisuals,
there are two ways you can do this.
1.
A bit of assiduity work in AfterFX paired with Resolume Arena.
You have to pre-produce a clip containing as many squares as you want to project on. With a bit of AfterFX knowledge it's getting easier to create a random flashing look in your clip. With Resolume Arena or something comparable you map your content on to your physical squares. Press Play!
If you are a bit lazy like I am
you can pre-produce a clip with for example 10 squares and double map them randomly spreaded over your surface.
2.
You can also do this just using Resolume Arena.
Create the same count of layers as you have physical squares. Build your scene inside the composition or use the layer routing to slice function. Map your scene onto your physical surface. Activate the Resolume auto-pilot for each layer. Place some pics or clips in every layer and play around with blendtimes and content duration.
For the "only Resolume solution" you can also do it the lazy way and just use a small amount of layers.
Have fun!
cosmowe
And by the way - I really love Rebel Overlay's work