If you ever wanted to use two LEGO pieces in such a way that studs go in two opposite directions, you would know that the majority of such SNOT (studs not on top) techniques are rather bulky, right? Here are two examples:
But there is a SNOT technique with no visible pieces except the ones used for your design. The closest my technique comes to “bulk” is that it leaves about half a millimeter of seemingly open space between your opposite-facing LEGO pieces. In the sewing machine on the right (my design), for example, it was used to attach an upside down gear lever, to represent a needle.
How do you make this kind of thing? It is simple. You need the two pieces you want to attach (facing away from each other) to one another – at least one of them should be brick height, as opposed to plate height.
You also need one or more technical 1/2 pins, depending on the size of the area you want to connect.
1) Using the short end of the 1/2 pin(s) as a LEGO stud, connect it to the back of one of your pieces. (If only one of your pieces is brick height, you now connect it to the other one.)
2) Push the long ends of the pins into the shafts at the bottom of the brick height LEGO piece. Since this is hard to take a photo of, with the first LEGO piece covering it, I took a last photo with the first piece removed.
And… voila! You can build your LEGO in two opposite directions!