Abstract: The invention relates to a method for producing a data carrier having a laser-markable layer and a transparent optically variable layer overlapping therewith at least in certain areas, wherein visually visible markings that at least partly overlap with the optically variable layer are produced in the laser-markable layer after the application of the optically variable layer. The invention further includes a data carrier produced by the method and a semifinished product, such as a data carrier blank, that is provided for processing by the method.

Abstract: In one embodiment, the musical box includes a box-like support structure and a music device disposed in the interior of the structure. A plurality of flexible continuous webs are sized to wrap around the outside of the structure. Each web has, along its outside surface, indicia representative of a particular mathematical data table, such as a multiplication table. One column of the table indicates the mathematical resultant of the remaining laterally displayed data. The resultant is disposed proximate a side of the support structure. A controllably movable strip or continuous web has a window and the window is sized to reveal one mathematical resultant. This continuous windowed web is driven by a gear and knob actuator.

Abstract: A computer including a base and a member superposed over the base and movable with respect to it. The base may be a card and the member may be a continuous flexible band surrounding the card. The band is slidable along the length of the card and also movable in the direction of its continuity. A series of dates, each including a month and day, is carried by one of the base and member, and a series of numbers is carried by the other. The dates are arranged in day-by-day sequence, and the numbers are in sequence with each successive number being larger than the one immediately previous to it by the amount of one day's fine. When the zero position of the sequence of numbers is moved opposite to the current date, the number adjacent the date on which a book was due will be the amount of the late fine.