Tom Davis discovered the new rod feature - the tuning: http://www.tetontenkara.blogspot.com/2014/01/turn-two-rods-into-four-experiments.html
This sounds a lot like the purple cow Jason Klass blogged about a while back. I am wondering if you could interchange different rod brands as well? Very interesting experiment.
It is not the experiment. It is the rod feature, available to TenkaraTimes rods fans.