The box contains the final gift, but first a series of puzzles must be solved in order to open the box. The project runs on an Arduino Mega. This is hooked up to several sensors, including a ...

Linda pulls a box from a stack of full shelves. “This one came from my father-in-law,” she says. “He thought he would stump me with the ‘World's Most Difficult Jigsaw Puzzle.’” ...