Thanks to Ken Clary, one of the GURPS Martial Arts playtesters, for sending this along.
It's a Polish martial artist who made, you guessed it:
Well, technically, they're knife nunchaku.
Is this real, or a good fake? For game purposes, who cares? It's good enough that when someone says, how the heck does your character wield sword-chucks without killing himself, you can point to Kacper Borowski.
I am compelled to mention that GURPS has stats for sword-chucks, in a box of cinematic weapons on p. 223 of GURPS Martial Arts. Largely thanks to Ken Clary and Sean Punch, but there you have it. The cinematic weapons box strikes reality critically once again!