The white square cubicle with a waist-high wall has a brown wooden door that looks like it has been repaired.
Speculation was that it could be the door through which Pistorius fired the shots that killed Reeva Steenkamp.
The cubicle was set up on the side of the court where the witness stand is. Two rectangular white stickers were visible on the door, one near the top and the other above the door handle.
Barry Roux, for Pistorius, and the paralympian stood behind the construction with their arms folded, talking before proceedings started.
Pistorius covered his mouth as he spoke. The accused, dressed in a black suit, had entered the court building without his usual entourage to escort him in.
He stood in the dock chatting to his lawyer Kenny Oldwage. Pistorius family members, including his uncle Arnold Pistorius, started arriving after 9.10am.
Oldwage and Roux then huddled in front of the door, talking and then called other members of their legal team over.
The cross-examination of State witness Darren Fresco,who was with Pistorius when two shots went off – one in September 2012 and another January 2013 – was expected to resume on Wednesday.
Pistorius is on trial for the murder of Steenkamp, who was shot through a locked bathroom door of his Pretoria home on February 14 last year. He said he had mistaken her for an intruder. – Sapa
— The Herald PE (@HeraldPE) March 12, 2014