I love it when I mail a letter, and it happens that I can create a theme. See my letter below. The envelope I made from an old calendar page, and it features a hummingbird. I used an address label with hummingbirds on it. I happened to have 2 postage stamps that featured a bird or birds. (My letter is 1.5 ounces due to extra enclosures, so it needed extra postage.) And I also put some bird stickers on it, front and back.
More on making your own envelopes from calendar pages, old maps, magazine pages, wrapping paper, etc: HERE.
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