A Japanese boy allegedly spent three weeks piecing back together a 10,000 yen bill like a jigsaw puzzle after it had been accidentally put through a paper shredder.

Japanese Twitter user ‘Tomo’ recently completed one of the hardest puzzles he’s ever done – putting back together a 10,000 yen ($65) bill that had been shredded into thousands of pieces. Apparently, his father accidentally shredded an old envelope at work after forgetting that he had put a 10,000 yen bill in it months ago. Realizing his mistake, the man decided to use his mistake as a challenging project for his son. He took home the entire shredder waste basket and told his son that if he could piece together the shredded bill and exchange it for a new one at the back, he could keep it. It was a daunting project for even the most avid jigsaw puzzle enthusiast, but one the boy gladly accepted.