This is my first instructable. The 2 optional steps are to make 2 different kinds of crossbows.

Step 1: Pieces

You need 2 yellow axles, 4 white axles, 2 green axles, 2 yellow connectors, 2 green connectors , 3 red connectors, 2 orange connectors , and 2 rubber bands. Optional features parts: crossbow: a white connector, 2 orange connectors, a red axle, and a blue axle. Alternative crossbow: 2 dark grey connectors, a blue axle, 2 green axles, and a white connector. You also need gray axles for ammo.

Step 2: Body

Attach the green connectors together with the white axle on one end. On the other end, attach the yellow axles onto the green connector. Attach the green axles to the ends of a red connector. Attach to the green connector under the white axle. connect 2 more white axles to the last place on the green connectors vertically. Attach the yellow connectors on to the white axles by the middle connecting point. Make sure they are going towards where the bowstring will be. Connect them together with a white axle. Pull the yellow connectors up and attach the orange connectors in the middle of the white axles.,pointing in the same direction as the yellow connectors are going.

Step 3: Bowstring

Overlap the rubber bands. Pull the overlapping loops through the other loops that aren't overlapping to create a knot. Thread one end of the knotted bands into one of the red connectors and put it in a slipknot to securely attach it. For the other side, the slipknot is about harder. You have to pull the end that you threaded all the way over the other side of the bowstring. Finally, attach the middle of the red connectors to the end of the yellow axles.

Step 4: Optional 1

Attach two orange connectors vertically on to the red axle. Put the white connector on the end. Attach a blue axle vertically on the other side opposite of the red axle. Attach to the red connector in its last place it can connect to.

Step 5: Optional 2

Attach the blue axle vertically on the white connector. Put the green axles on the areas to attach one attaching place away from the blue axle. Attach the gray connectors on the the green axles on the connecting area right by the big gap. Attach to the same spot as optional 1.

Step 6: Shooting

Pull a gray axle back with the rubber band, center in the gap in the body, aim, and fire.