The "Harry Potter" series of books, written by J.K. Rowling, and the movies that followed are a worldwide phenomenon. In the second edition, "Harry Potter and the Chamber of Secrets," Ron Weasley receives a magical letter from his mother known as a howler after using his father's magical flying car to get to school with Harry. Once opened, the letter shouts at Ron with the flaps of the envelope serving as a pair of lips.
Fold one corner of the square over to its opposite corner, creating a triangle shape, and then press the fold flat to form a crease.
Hold the triangle with the long edge near you, and fold the right corner straight across the long edge. Crease the folded section to create a crease perpendicular to the long edge, creating a smaller triangle approximately one-fifth as long as the original long edge.
Fold the left edge across, straight along the long edge of the initial triangle, so that the folded flap overlaps with the right flap. This flap must be longer than the left flap in order to reach across the initial flap.
Grab the section of the left flap which overlaps the first section, and fold back to fully expose the right flap again. Fold back the point of the right flap with a matching fold to the fold made in the left flap. The two flaps will each end in a small triangular point, with the two points touching.
Fold the top of the small triangle of the right flap down, so the edge creates a straight line parallel to the long edge of the original triangle. Repeat for the left flap.
Unfold the paper and then turn it over. The prior creases will provide guides for you.
Turn the paper, so one of the corners with creases is facing you. Then fold the point in to the first point; the creases touch the long crease running between opposite corners.
Pinch in the sides of paper on either side of the folded triangle. The creases will allow this to create a small section which pops up off the paper as you pinch in, creating part of the lips.
Fold, and then pinch the opposing corner to create a matching lip section; then flip the paper over.
Fold the near corner up along the crease running perpendicular to the long crease; then pinch the lip section in. Repeat for the opposing corner to cause the lips to come together.
Turn the paper, so one half of the lips is near you and the other farther away, with the left and right corners left-pointing out; then fold the top set of lips up.
Fold the two remaining corners in, so the folded edges run along the edges of the lower lip section, and then fold the top half of the lips back down. The letter will now be rectangular with raised lips.
Fold the left and right edges of the letter in to touch the sides of the lips to complete the howler. Push the sides together, and then pull apart to make the howler "talk" by moving its lips.