The helical scan methods use a recording drum with a diagonal axis of rotation. The tape is wrapped longitudinally around the drum by idler wheels, so the tape heads, instead of moving across the tape at almost 90° to the direction of motion as in the quadruplex system, move across the tape at a shallow angle, recording a long diagonal track across the tape. This allows an entire frame to be recorded per track. This simplifies the electronics and timing systems. It also allows the recorder to be paused (freeze-framed) during playback to display a single still frame, by simply stopping the tape transport mechanism, allowing the tape heads to repeatedly pass over the same track.