a simple gun made of a few knex pieces and a rubber band made to fire paper clips.
Step 1: Build it
take 2 yellow sticks and a connector with ony 2 clips side by side and connect the sticks into the connectors.
Step 2: Finishing
take an end connector with only one slot and thread the rubber band thru thru the hole. Put one end of the rubber band thru the other and make it tight. take another connector and do this again with the same rubber band so the rubber band should be tightly on both. Attach to the ends of the yellow sticks.
Step 3: Firing
hold the gun by the other end opposite of the band. (it should look like a triangle) put the rubber band thru the rubber band by the opening of the clip. pull back by the paper clip and fire. goes very far if you have a tight rubber band.