Step 2: Fold one side to the other by about one third.

Step 3: Fold the open edge of the upper layer of paper in the opposite direction.

Step 4: Fold the lower paper in the same direction.

Step 5: the angle of the wide side faces the inward line, and the angle of the narrow side takes the same straight line position, and the right triangle is folded inward.

Step 6: Fold the narrow side to the wide side along the straight line.

Step 7: Spread the folded ingots.