Duo X Neodymium magnet
For use with magnetic nail polishes.
The Duo X neodymium magnet pulls the particles into an X shape on the nail. Simply hold the magnet 1/4 inch away from the nail for 15-30 seconds, with the cameo over your nail and looking AT your mani to achieve the X effect.
Short video demonstration here:
A single neodymium bar magnet pulls the particles into a line across the nail.