I built a pullback Rat Rod with the usage of Technic parts, and a pullback motor. I built the vehicle because I saw pullback sets at Walmart, and it inspired me to use some of my parts to build my own. To give it a unique function I added a cylinder block that is powered by the front wheels turning. I believe that this would make a great LEGO set because it combines a pullback function along with a cylinder block. Using the parts from this set people could make more models with parts that are not on other pullback sets.