Very nice Willis, had to look pretty hard to figure out where the mirror is!
I use a mirror called "scientific mirror" also used as one way glass.
In the first pic the ordinary side of the glass is held up to the styrene road, in the second pic the coated side is held against it.
You'll notice the gap is visible on the ordinary side but not on the coated side.
The third pic is two mirrors angled at ninety degrees to create an intersection, although they are not positioned right in the photo you'll get the idea.
When they are secured in place the seams disappear.
There is only one truck in that pic but you see two trucks. The cool thing is you can have a trailer with one name on it and a truck with another to really sell the illusion!