I am sure it doesn’t matter, but unless the track is running in a circle, the pivoting arm will produce a very slight chirp in the tone.
The example of a linear tracker with a moving overhang is obviously not something that one buys… but it was yet another example to convey the effect of what is happening with the arm, that makes the platter look like it is advancing or retarding as the arm moves inwards.
What was an “ah ha” moment for me, was obviously not shared well or described too clearly.