It's terrifying. From your comment I was thinking negative stagger like has been done for a few designs in the past, not a lower wing that sweeps the entire len

It's terrifying. From your comment I was thinking negative stagger like has been done for a few designs in the past, not a lower wing that sweeps the entire length of the aircraft, with the upper wing at the tail. The angle where the rear wing is exposed to interference from the lower wing ranges from 15 degrees through 90. Losing lift on that rear wing, which there is a massive range of opportunity to do, will yank the rug out from under the back of that aircraft. How often will this design suddenly decide to fly tail-first tens of feet away from touching down on the tires?