Yes, you can embed an Halbach Array, even into your own Papercraft projects!
And what the heck's an Halbach Array?
Just put a lot of Magnets on a row, each one 90 degrees rotated in relation to the previous one, like this..
Tada! An Halbach Array.
In that picture, almost all of BOTH the magnet's poles strenght is on the bottom side!
So where to get a lot of Magnets, say, for a Papercraft Toy Monorail?
On the Magnetic bands you find on the doors of discarded Refrigerators, that's where!
Get a Compass, and find the North pole, that's the side of the band that attracts the South side of the Compass, the bar is on the left:
Cut the band in sections as long as the band's thickness, in this case, 2 mm, notice you better paint the North side, it there's not a groove on it, so as to tell the poles apart... I went ahead, and did both! LOL
You'll get a lotta magnet bars, Mwahahahahah!
Then, it's child's play, glue one, rotate, glue another, rotate, etc, see the graphic above, on the intro.
It cycles at every 4 magnets...
You see a completed section, here, notice the repeating pattern, you spot a groove on every 4th bar.
After you're done, cut the Plastic and turn the thing upside down, remember the strenght is now almost all on the side where there's only a clan plastic strip.
Lots less mess and friction, that way.
The following is a Prrof-of-Concept makeshift thing, so you can and will make something a lot better-looking, notice, the underside has all the strenght, so it's turned up, so the magnets on the strip and that top magnet repel each other.