onward

There stretches out in all directions a seemingly infinite desert plain. Someone is crossing, a figure dragging behind themselves a tube that is almost as wide as they themselves are tall. The tube stretches back in a straight line, its origin far beyond the reach of sight. The figure drags it onward, no destination in view.

Now see the broad rank of figures, all roughly abreast, dragging their parallel tubes. What could have started something like this, and to what end could this pilgrimage be going?