"Motion Security Thread" is an embedded thread that contains thousands of microscopic lenses which create a moving image effect when the banknote is tilted.
The information about the technology is here:
http://www.crane.se/site.aspx?id=572The first banknote with the motion thread was 1000 kroner from Sweden. Since then, the following banknotes were also released:
Mexico 200 and 1000 pesos (100 and 500 not yet released)
Paraguay 100,000 guaranies
Korea 50,000 won
Denmark 50 kroner (100, 200, 500, 1000 not yet released)
For the images of the notes, check out this site:
http://www.banknotenews.comIn 2010, the new US$100 will also feature the motion thread.