English: Q-cumber, seen here sometime in 1955, was among the earlier examples of a full-scale magnetic mirror device, built to Richard Post's designs at the Lawrence Livermore Laboratory, today's LLNL. A magnetic mirror is a simple device consisting primarily of a solenoid, which can clearly be seen here in the center of the device. At either end are additional windings, contained in the disk nearest the camera, which increase the magnetic field at either end. Q-cumber, so-named for its shape and a reference to the value "Q" used in fusion, was the centerpoint of the lab's report on mirrors when declassified at the Atoms for Peace conference in Geneva in 1958. The papers demonstrated clear evidence that Q-cumber did indeed confine a plasma, although in this case, for a very short time.