There is a prototype stamp. This set of stamps is very interesting. It can be torn into a circle or a square, and only 1-3 corners of the square can be torn off according to your preference, so that the stamps can take on various shapes. Sticking them on the envelope will be more interesting. As long as the postage and memory are complete, it will not affect the delivery.

There is another set of stamps which is similar to this set of stamps. It is the 25-6J, World Earth Day stamp issued on April 22, 25, with one set.

At first glance, this set of stamps looks like a special-shaped stamp, but it isn't. Although there are circular perforations in the middle of the stamp, there is no postage and inscription in the circular face. That is to say, the circular part of the stamp is not a complete stamp, and it must be surrounded by a square frame, so it is not a set of circular stamps.

and that's what's interesting about it. Since the postage and the stamp are on the square frame, if you tear off the circular pattern in the middle and leave only a stamp frame on the envelope, it should be possible to post it. It's really interesting.

Although this set of Earth Day is not a special-shaped stamp, it is indeed another kind of stamp related to "special-shaped"-a stamp with special-shaped perforations (notice the four-corner star-shaped perforations marked with red circles in the picture).

stamps with special-shaped perforations refer to stamps with non-circular perforations. The picture on the left shows the first set of stamps with special-shaped perforations issued in China. On June 27th, 1998, a set of three stamps of He Xiangning's traditional Chinese paintings was issued. Note that the place I marked with a red circle is a flat circular perforation, one on the left and one on the right. If you don't know, you may think it is a torn perforation.