Soft and stiff slabs were inter-layered (giving eight layers total). Then the piece repeatedly cut in half and slammed downward to re-flatten. Eleven times (doubling the number of layers each time to get 16,536). Yet it is still not mixed! 30 seconds of wedging is all it took to finish the job. Wedging is a very effective mixing technique. A pugmill would easily mix this also.
The process of mixing a plastic clay by hand before forming it. Similar to kneading of bread dough, it is considered an essential step by most potters.