Really enjoy playing with this. As others have noted, would find it more usable if the colors indicated source types (but acknowledge the purposeful intent to keep this instrument less predictable for the sake of playfulness).
A bit off-topic, but I might actually find this approach useful for music production, especially if I could just drag and drop a folder of samples into a grid in an M4L plugin.
Very cool - I still find Reich's looping sample experiments inspiring!