How to fold a Ninja Star

Steps

Step 1Start with the white side up. Fold the bottom edge up to the top edge, crease, and unfold.
Step 2Cut along the crease to make two equal rectangles.
Step 3For a two-color star, swap the lower rectangle for half of a different-colored sheet cut the same way. (For a one-color star, just keep it.)
Step 4Begin with the upper sheet (sheet 1). Fold the bottom edge up to the top edge to make a long strip.
Step 5For the lower sheet (sheet 2), fold the top edge down to the bottom edge. From here on, the two sheets are folded as mirror images of each other, top to bottom.
Step 6Fold sheet 1 in half, right end to left end, to crease the middle. Unfold.
Step 7Crease the middle of sheet 2 the same way, and unfold.
Step 8Sheet 1, right end: fold the top corner down to the bottom edge to make a triangle.
Step 9Sheet 1, left end, the opposite way: fold the bottom corner up to the top edge.
Step 10Sheet 2 is folded the opposite way from sheet 1. Right end: fold the bottom corner up to the top edge.
Step 11Sheet 2, left end: fold the top corner down to the bottom edge.
Step 12Sheet 1: fold the right half up along a diagonal that starts at the bottom of the middle crease.
Step 13Sheet 1: fold the left half down along a diagonal that starts at the top of the middle crease.
Step 14Sheet 2 goes the other way: fold the right half down along the diagonal.
Step 15Sheet 2: fold the left half up along the diagonal. You now have two mirror-image units.
Step 16Turn sheet 2 over.
Step 17Rotate sheet 2 a quarter turn so that it lies sideways.
Step 18Lay sheet 1 across sheet 2 to form a cross, with the center squares exactly on top of each other.
Step 19Fold the triangle of the lower unit that sticks out on the right: fold it to the left along the right side of the center square, and slide its tip into the slit at the center, under the upper unit.
Step 20Fold the triangle that sticks out on the left the same way, to the right along the left side of the center square, and slide it into the slit on the other side.
Step 21Turn the whole model over.
Step 22Fold the triangle that sticks out at the top down along the top side of the center square, and slide its tip into the slit at the center.
Step 23Fold the triangle that sticks out at the bottom up in the same way and tuck it in. When all four points are locked together, the ninja star is finished.
Finished