and twelve
o'clock
Finally , he satisfied the softly insistent gong by standing up and gazing in turn at each of the three doors spaced around the cylindrical chamber . He deliberately adopted an expression of simple-minded anticipation as he ambled over to the nearest one . The door was round , about four feet in diameter , and set in a flattened part of the wall with its lower edge tangent with the floor . Rods about two inches thick projected a hand 's breadth at four , eight , and twelve o'clock . The markings around them suggested that each could be rotated to three different positions . Barnsley squatted on his heels to study these . Noting that all the rods were set at the position he had learned to think of as `` one , '' he reached out to touch the door .