| 摘要 |
Two plastic film transparencies are rotatably attached side-by-side by engagement of film portions on one transparency with at least one incision on the other. There are images on each transparency and the rotatable attachment allows relative rotation of the transparencies to overlay the images on the transparencies. The images are cooperative so that overlaid images provide cooperative images. The rotatable attachment is accomplished by film portions on one transparency engaging an incision or incisions on the other. In some embodiments of the subject invention at least one of the transparencies is essentially circular. In all embodiments of the invention the relative rotation of the transparencies is in a range of 10° to 360°.
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