GG2U - Magic Jigsaw Puzzle offer not possible?

I saw this offer and figured it'd be an easy 5 bucks. You need to get 5000 coins within 7 days. This issue is I'm not sure this is doable. You only get a handful of coins for each completed puzzle, and you have only 7 days to compete the offer. The amount of time needed doesn't feel worth it. Has anyone actually done this offer?