When the Berlin Wall came down, the East German secret police, known as Stasi, knew their days were numbered, so they began to shred their extensive files. And when the shredders broke down, they tore documents into pieces. What they left behind is the biggest jigsaw puzzle ever. Twenty years later, little progress had been made reconstructing documents from the six hundred million pieces of paper, according to Joachim Haussler of the present Stasi archives authority.
So now the authorities are turning to technology. Computers, says Haussler, are "quicker, cheaper and can match and remember things humans can't". The particular computer taking on the task is the "ePuzzler" made by the same people who invented the mp3 player - the Fraunhofer Institute in Berlin.
Bits of torn paper of all shapes and sizes are taken out of the sacks, ironed flat, then scanned.
Each piece, however small, is given a computer file into which is entered any information about, say, paper colour, handwriting or print on it, any significant acronyms that might link it to a particular Stasi office.
Then a complex mathematical programme is brought into action matching that information and the paper's shape with other fragments from among the millions.