Start off with simple models to guarantee a firm understanding of the basic principles at play, and then move onto larger, more complex models to push the machines harder and see how they can work together. Also included is a specially designed spring scale so that you can measure how the machines change the direction and magnitude of forces, making work easier to do. With this durable, modular construction system, you can see how the same basic elements combine in different ways to form each machine. The models can be assembled and disassembled again and again; combine the pieces to create your own configurations, limited only by your imagination!