> Very curious, since there were commercialized versions reported back in 2019. (1) Their patent application was filed on 11/6/2017. https://patents.google.co

> Very curious, since there were commercialized versions reported back in 2019. (1) Their patent application was filed on 11/6/2017. https://patents.google.com/patent/US10836466B2 https://patents.google.com/patent/US10836466B2 (2) This propeller is different from those propellers, and the patent office found that the differences were patentably new and non-obvious. Claim 1 is representative: > 1. Toroidal propeller comprising: a hub supporting a plurality of elongate propeller elements in which a tip of a leading propeller element curves into contact with a trailing propeller element to form a closed structure with increased stiffness and reduced acoustic signature. The element "in which a tip of a leading propeller element curves into contact with a trailing propeller element" seems to be common to all the independent claims of the patent.