[PetitPrince]

> imagine a spinning display like those of the article but somehow tuned so that they are only visible when exactly head on

I don't understand: doesn't defeat the purpose of a volumetric display (seeing what is displayed from multiple point of view) ?

[two_handfuls]

This would be a poor man's "lightfield" display: as you move left or right you see a different perspEctive, just like you would if it were a physical object on the table instead of the spinning screen contraption.

So you would indeed see different points of view.