This puzzle is inspired by a puzzle described in various sources (CAS Musings, Math in the Middle, YouTube). Let us know if you know the origin of this puzzle.
The puzzle starts as a 4 × 4 square with three parallel slits (of length 2). You can fold the puzzle only along the grid lines. There are four goals: to fold the 4 × 4 puzzle down to a 2 × 2 square that shows one of four patterns:
The first two are relatively easy, while the last two are relatively hard. You can only get each of these patterns on one side of the folding. It doesn't matter what's on the other side of the folding.
The PDF file is the best combination of printing quality and small file size. The PostScript file also has ideal printing quality, but the file is larger. In either case, you need a suitable viewer. Alternatively, you can print one of the images. If you can print images scaled to fit, use 150dpi. Otherwise, use 72dpi.