Need ideas for a nail sorting mechanism that lines 20 nails parallel to each other.?

I have to line 20 nails parallel to each other, without using any electricity and have 10 facing one way and 10 the other way in no specific order.Need ideas for a nail sorting mechanism that lines 20 nails parallel to each other.?
Interesting problem.





I would utilize the fact that the head is bigger than the pointy end. You can use the same mechanism for each direction, just change the way you put them down.





You can sort them initially with gravity. Shake a board with nails on it, while tilting the board and they will all roll so that the head is downhill. That is a start, but you can't have too many on the board or they get in the way of each other.





Another way to sort is with a weak magnet. The magnet needs to be strong enough to capture the large head, but too weak to hold it from the pointy end. You can use 10 magnets so that you only get 10 at a time which you can put on a table facing any direction you like.





Or, form the image of the nail pattern, 10 one way and 10 the other, so that a nail fits in the impression half way, then vibrate the form until a pile of nails all find their way into the pattern. Then tilt the form to remove the extra nails.





I hope one of these helps.