Heh. I finished off all 400 puzzles in the main level of the iOS game Picture Cross- Picross / Griddlers / Paint-By-Number / Nonograms are all names for that kind of puzzle. This version had a pretty decent UI, which is tricky for screens with small squares and fat fingers. I'd recommend paying a bit for the upgrade that gets rid of the ads, but then just rely on the bonus tokens they give you if you pop open the app every day.
"The transformers holding back tears as they load a hearse into a slightly larger hearse"