Lay the piece of paper on a firm, flat surface. Fold both sides along the diagonal, forming heavy creases, then unfold. Fold the top and bottom corners down to the center. Make a crease on each corner, and fold under so the corners are hidden. Fold these parts down again to the center. You will then have two diamond shapes at the ends.
Fold the top flap up and the bottom flap down on the left side to form a triangle on both top and bottom that match the triangle at the left end. Fold the entire left side over to the right so the left triangle tip touches the left tip of the diamond on the right side. Fold all the triangles toward the center on the left flap. Fold the top and bottom corners toward the center on the left flap. Fold the triangle flap over the the left so it touches the edge on the left.
Fold the top flap up and the bottom flap down on the right side to form triangles. Pull the right flap over to the left so only the triangle sticks out from the left. Fold all triangles toward the center. Fold the corners toward the center. Fold the triangle flap that is produced toward the right so the tip touches the right edge.
Pull the triangles on the top for the box to pop up and open to reveal the surprise gift or card within.