The origami-style folding cover found on Cygnett's Enigma ($40) isn't novel -- we've seen it on full-sized iPad cases before -- but it is the first one we've come across for the iPad mini. There's a simple hard plastic shell to hold the tablet in place, leaving the top edge fully exposed. We find this design to be more acceptable along the bottom, as the opening only runs a little past the speakers. Weak magnets in the cover hold it together to form…