This CANNOT Exist... (And Yet It Does)

*** TODAY’S PUZZLE *** [Simon writes] I’m pretty sure now that this was a prank by Mark and that he didn’t think I’d actually try this puzzle once I saw what it was... it’s called Self-determination and it’s the (unbelievable) work of Stephane Bura. It is the most daunting ruleset/grid combo I think we’ve ever seen. Good luck!! Please do leave a comment if you enjoy this video - in our opinion, Stephane deserves all the plaudits in the world for somehow creating this one. You can try it at the link below: Rules: Place the digits 1 to 8 in each row and each column. Each horizontal domino that has both its digits in the first 7 columns forms the coordinates of a digit in the grid: The leftmost member of the pair is its row. The rightmost member of the pair is its column. Its value is the row in which the pair is. For instance, if R4C1 contains 7 and R4C2 contains 5 then R7C5 cont