A postage stamp is evidence of pre-paying a fee for postal services. Usually a small paper rectangle that is attached to an envelope, the postage stamp signifies that the person sending the letter or package may have either fully, or perhaps partly, pre-paid for delivery. Using postage stamps is the most popular alternative to using a prepaid-postage envelope. Stamps have been issued in other shapes besides the usual square or rectangle, including circular, triangular and pentagonal. Sierra Leone and Tonga have issued self-adhesive stamps in the shape of fruit; Bhutan has issued a stamp with its national anthem...