A team led by Tony Sale built a working copy of a Colossus Mark 2. The plans and machines had been destroyed, but a surprising amount of other material was not destroyed. It was mostly in engineers' notebooks, much of it in the U.S. The optical tape reader might have been the biggest problem, but Dr. Arnold Lynch, its designer, was able to redesign it from his own first writings. The rebuilt Colossus is on show at The National Museum of Computing, in H Block Bletchley Park in Milton Keynes, Buckinghamshire. This is where the Colossus No. 9 was used in the war.