There's a jigsaw brand (impossipuzzle, I think) that does something like that to make them as difficult as possible. They're printed on both sides, and the rows

There's a jigsaw brand (impossipuzzle, I think) that does something like that to make them as difficult as possible. They're printed on both sides, and the rows/columns are cut from different sides. I have aunts that took almost a year solving one that was an 5*7 foot picture of baked beans and chips. Most of the patterns are repetitive and non-distinct on purpose.