What's Wrong With This Joke was TandemSpeed Limit 2156

Peachicken wrote (with me editing for space):

This is a random event that is at most able to convey information FTL than is the "writing speed" of a giant-size wide-screen oscilloscope with a small ray gun that responds well to high frequencies.

Suppose you have an oscilloscope that has the "time base" or the "X Value" angularly move a laser east-west, and the "Y-Input" (whatever signal varying with time, possibly an oscillating signal with frequency a north-south.

Suppose the laser is moved angularly back-and-forth east-west .3 degree 2,000 times a second, and does so north-south .3 degree 8,000 times a second, with movements being peak-to-peak values and the movements being sinusoidal. I surely believe this can actually be done!

For the sake of this argument, this hypothetical experiment can angularly move a mirror that reflects a laser beam in lieu of moving the laser in such a fashion. Movement of the mirror has the additional advantage of only having to have angular movement of half the angular movement of the reflected laser beam!

Now, aim the laser at the moon, 235,000 or whatever miles away!!!

Looks like this writes a "Lissajous" pattern on the moon, with overall dimensions roughly square and able to fit on the moon. As in about 1230 miles on each side of the "square".

This surely sounds not only physically possible, but outright achievable!!!

So the beam moves north-south along the lunar surface up-and-down 1230 miles 8,000 times a second, 9.84 million miles a second. If fastest speed coincides with fastest east-west speed of 1-4 that, then the "dot" moves at 10.14 million miles per second - and "C" is .186 272 million miles per second! So what does this prove some movement known to move faster than C? Surely this is not even an argument of transmitting info faster than C! And if a big bunch of librarians with good stopwatches reshelve books in a huge library in some "Wave" that travels faster than C, this does not indicate info travelling fater than C... For that matter, librarians downstream of a disruption of such a FTL "reshelving wave" restore the "FTL reshelving wave" before they learn of the disruption!

I don't see how anything travels faster than light when all superluminal speed is of absence of anything. However, "waveguide" reminds me of this "phase velocity-vs-group velocity" business, since a common form of waveguides is a place where this often occurs.

Given the amount of time not only for the jump to occur but also the amount of time required to wait for the jump to occur or to respond to this jump occurring, I surely believe this to nopt believe this to be a mechanism to transmit info FTL from the cause of the jump to the output of whatever detected that the jump has occurred.