These pieces are like plastic mechano. They are meant to be glued together with a low temperature glue gun for an education project and then broken apart for the next group.We made them for a hydrogen fuel cell car workshop, as a collaboration between http://www.arcolaenergy.com/ and http://www.learning-to-learn.org.uk. Thanks to Simon who put together all the wheels and bars.The fuel cells come from Horizon: http://www.arcolaenergy.com/store/And we bought gearboxes from rapid: http://www.rapidonline.com/Educational-Products/Electronics/Motors-Gearboxes/Economy-gearbox-and-motor/10556/kw/gearboxSheet 1: The small circles are to be glued (with acrylic glue) onto the bigger circles to provide enough surface area for them to be hot glued onto 4mm axels.The longer bars with holes in are for holding the 4mm axels.Sheet 2: This is probably only useful for fuel cell applications, as it holds a 5ml syringe pressurized with an elastic band.