What I find interesting in this scene is that most of it has been flipped (note 3PO's streak) as though there's a missing section, and that the "transport" was mean't to be approaching 3PO (instead of being a black triangle/nothingness).
Referenced in this script sample:
EXT. TATOOINE - DUNE SEA
Threepio, hot and tired, struggles up over the ridge of
dune; only to find more dunes, which seem to go on for endless
miles.
He looks back in the direction of the now distant
rock mesas
THREEPIO
That malfunctioning little twerp. This is all his fault!
He tricked me into going this way, but he'll do no better.
In a huff of anger and frustration, Threepio knocks the sand
from his joints. His plight seems hopeless, when a glint of
reflected light in the distance reveals an object moving
towards him.
THREEPIO
Wait, what's that? A transport! I'm saved!
The bronze android waves frantically and yells at the
approaching transport.
THREEPIO
Over here! Help! Please, help!
