Abstract: Various improvements relating to digital watermarking and related technologies are detailed, including methods that enhance security and functionality, and new articles including watermarked puzzles and marked DNA.

Abstract: This disclosure describes methods and systems for visibly altering a security card in response to detecting a change in access permission, such as an event that invalidates the card. In one implementation, a machine-readable code on the card carries an index to a database of access permission information. A reader extracts the code from the card when its bearer presents it for validation. The reader looks up the access permission and either permits access, denies access, or invalidates the card. One mode for invalidating the card visibly alters the card so that other personnel can identify the card as being invalid through visible inspection.

Abstract: Various improvements relating to digital watermarking and related technologies are detailed, including methods that enhance security and functionality, and new articles including watermarked puzzles and marked DNA.

Abstract: A toothbrush including a head region in which is secured bristles on the top side of the head region, along at least a portion of the length of the head region. A neck region is connected to the head region and an elongated gripping region is connected to the neck region. The head and neck regions are both angled backward from the gripping region. An end rest region having a generally flat bottom surface is connected to the gripping region. The gripping region arches frontward of both the neck and end rest regions. The head and other handle regions of the toothbrush are of a material composition at least a portion of which is recycled plastic; preferably, the material composition is at least about 90% recycled plastic. At the time of disposal of the toothbrush of the invention, say, when its bristles are worn out, the entire toothbrush can be preferably recycled instead of included in non-recyclable trash.