Play Catapult

Lay three chopsticks on the table in the shape of a triangle. Overlap each corner. Rubber band the corners together.

Make a freestanding pyramid with three more chopsticks. Keep the thinner part of the chopsticks toward the top. Secure the top of the pyramid with a rubber band. Secure the bottom of each leg of the pyramid to a corner of your triangle that you made with the other three chopsticks.

Create three holes in your plastic cup with your pen. The holes should be right under the rim and evenly distributed.

Tie a rubber band into each hole. Make sure your knot is secure.

Move your pyramid so the triangle that was laying on the table is now facing you. The cup should have its opening face you. Tie an end of each of the bands on the cup to a corner of the triangle. The cup should be in the air with the top of your pyramid farthest away from you.

Turn your catapult around so your cup's opening is facing away. You can load it with whatever you like. Pull back on it and let go. You will catapult the cup's contents. Make sure that you hold onto the back of your catapult for extra support as needed.

Drill holes in the rulers large enough for the carriage bolts to fit through. Use the measurements given on the ruler as a guide for where to drill the holes. Make the holes as centrally as possible. Drill holes in four of the rulers 1/2 an inch from the end and, measuring from the same end, 10 inches from the end. In the last ruler, drill at 1/2 an inch and 3 1/2 inches from the end.

Lay the brick with one of its long, narrow edges on the table. Take one of the four rulers with the shared sets of holes. The brick has a set of three holes in a row which act as an air gap. Start with one of the holes on either side, but not the middle one. Take the ruler and position the hole that you drilled 1/2 an inch from its end and place it over the air gap hole. Push a carriage bolt through the hole in the ruler, through the air gap hole and out the other side of the brick. Slide the 1/2-inch hole of another ruler over the protruding end of the carriage bolt. Tighten a nut over the end.

Do the same with the second pair of rulers using the air gap hole at the other end of the brick. Bring the ends of the rulers on each side of the brick together to make triangles. Overlap the 10-inch holes of the rulers on each side of the brick. Slide a carriage bolt in through the first pair, then attach a nut and screw it tight against the rulers.

Add another nut and position in the center of the carriage bolt. Take the remaining ruler and slide it on to the bolt, slipping the bolt through its central hole. Fix another nut on the other side of it. Slide the tip of the bolt through the hole in the remaining pair of rulers with a nut on each side of them to keep it tightly in place.

Drill another set of holes just where the rulers which form the triangles come up over the edge of the brick. Slide carriage bolts through these holes and fasten in place with nuts.

Tie the dumbbell weight to the short end of the central ruler, putting the string through the 1/2-inch hole. Place the plastic cup against the other end of the ruler and tape into place. Pull down the cup end of the catapult, place the ping-pong ball inside and fire.

Lay out two 12-inch posts parallel and close together. Lay out two 6-inch posts, one perpendicular to each 12-inch post, sticking out at the same point about a third of the way down each 12-inch post.

Cut the paneling into triangular pieces that will cover the shorter pieces and also attach to the longer pieces. You should have two pieces that look like a reflection of each other. Use wood glue and nails to attach the two pieces.

Stand the two sections up and connect them at each end with a 6-inch post underneath, using glue and nails. Connect the two now-vertical posts on the standing sections with another 6-inch post. Use screws to attach this piece, because you may want to lower it to change the trajectory of the catapult.

Drill holes through the triangular pieces and the posts, in the middle of the side of the triangle attached to the post. Also drill a hole through one end of another 12" post.

Cut off 15 to 20 feet of twine and twist a wire onto one end of it. Set the 12" post that you just drilled between the two 12" posts that are the base of the catapult's body. Thread the twine through all three holes as many times as you can, using the thread to guide the head of the twine through.

Use the remainder of the string to make figure-eight wraps through the side sections but not through the middle post, which will throw your object. When you push the arm back and twist it, you will also twist the twine, building up torsion.

Glue or tack a Dixie cup to the opposite end of the throwing arm from the rope; this cup will hold the items you're shooting. Secure an eyehook at the end of this arm and on the 12" support posts in each side. Thread a wire hanger through all three hooks. When you yank it out, the catapult will go off.

Lay a square piece of paper in front of you, with a corner facing you.

Fold the paper in half, bringing the right hand corner to touch the left hand corner, creating a vertical center line. Unfold.

Bring the bottom corner to touch the top corner. Pinch the paper at the center line, to create a center point. Unfold the paper.

Fold the top corner about one-third of the way down. The point should rest on the vertical center line to keep everything even.

Fold the upper left hand edge of the paper in to the right. What was the left side of the top edge will rest squarely along the top of the vertical center line. Fold the upper right hand edge in. Folding these two edges creates a hidden pocket at the top corner of the model.

Open the paper slightly, and then pull the hidden flap at the top corner out and up. Keep the upper right and left hand edges folded down. The hidden flap will stick straight up and looks like a triangle.

Fold the new upper left edge all the way in to the right, so it lies along the center line. Fold the upper right edge in to the left, so it also lies along the center line.

Fold the bottom corner of the model up and behind, so that it touches the back side of the upper corner. Flatten the crease. The model should resemble a peacock.

Fold the entire model in half along the vertical center line, bringing the left corner to touch the right.

Rotate the model to the left, so the upper point now points to the left. Pick the model up.

Hold the bottom of the model in your right hand, while you use your left hand to pull up on the left triangular flap. Keep pulling the flap up until it's even with the upper edges of the base of the model. Then, pinch the bottom of the model to keep the flap in its new position.

Fold the upper left and right edges of the base of the model down, so the corners are even with the bottom edge of the model. This allows the catapult to stand on its own.

Open the triangular flap slightly, creating the bowl of the catapult. Load the bowl, then pull the arm back toward the base of the model. Release it to fling the projectile.