I know I ought not to mix languages - but I did - did anyone notice the Wortspiel?
So Jörg would like to try - and "warum nicht"=
So some close-ups of the footwear:
It seems like a platform with loops for the feet, depending on the tact.
These people seem to be on skates , maybe special ones?
I don't think I have seen this design before - so I included a few extra images to help. Again, the loops indicate to me that the feet can be placed in different arrangements depending on tacking
I have some images for traction kites - best look at other blogs in other years, in the months of January and February.