In article ,
Mark McIntyre wrote:

Same with a very narrow angle pair of scissors
the crossing point can be made to advance at c (at least in
principle).

[...]

This is one of the classic paradoxes of SR. You're applying newtonian
mechanics, which are inapplicable.

The question of the crossing point is not a mechanics problem. No
physical object is moving at relativistic speed.

I suggest you do a quck websearch
for it

I did that. The first page I found is

http://math.ucr.edu/home/baez/physic.../scissors.html

It considers the case of some scissors with blades a light year long,
and indeed if you are relying on the distant end of the scissors to
start moving then it will be delayed - the end can't start moving
until the force has been propagated down the blades.

But as that article points out in the last paragraphs, this does not
apply to scissors where the blades are small enough and the motion
slow enough that the whole blade is moving before you start measuring.

This - not the giant scissors which I had not heard of before - is the
case that I and (presumably) the original poster were considering.

-- Richard