Kan't Kopy paper

Kan't Kopy safety paper is a type of paper printed with a patented moiré pattern that, when photocopied or scanned, produces a repeated pattern of the word "VOID" on the copies. It is available in 250 sheet packages and no software is required. It is used for coupons, certificates, checks, and games. The paper comes in red, blue, and green. The illusion of the "VOID" pattern is created by line segments intersecting at various angles.

References

* [http://www.kantkopy.com/technology.html Kan't Kopy safety paper technology]