This is an original work by my daughter, with a bit of help from me, with a bi-directional interlocking tile, ala Escher (in pen and ink, on poster board). This is actually surprisingly hard to pull off. Though Escher did birds, he did not do a swan in this style. As usual, click to enlarge:
The trick is to take a square piece of paper, and rotate whatever you cut from two sides to the other two adjacent sides. We destroyed a lot of post it notes until we got there. You can still see the ghost of the original square, with corners at the tip of the swan's head, the top of its wing, under its wing, and at the bottom of the neck.