Beatrice do the Watusi + design

The buoy chair, by Evan Dewhirst/Achille Castiglioni
Designer Evan Dewhirst, exhibited his Buoy Chair at ICFF 2009, he says:

The Buoy Chair combines simple construction and green manufacturing to create an iconic form. It promotes healthy, ergonomic sitting habits by engaging the user’s stomach and back muscles to provide stability. It also allows great lateral mobility for use at large surfaces while still providing comfort and support. Whether it lives in a classroom, studio, bar, or office, the Buoy Chair is a playful and healthy alternative to current seating options.

Below: Sella stool (1957) by Achille Castiglioni
Sella (saddle) is the pivoting stool that garnered the Castiglionis an incongruous "Dadaist" label. With this seat, the brothers designed a new behavior, a hybrid between sitting and pacing nervously, because, says Achille, "When I use a pay phone, I like to move around, but I also would like to sit, but not completely."

same/different design?