Children are given boards from a waste pile of boards. They learn the merits of being polite and asking for permission. The children decide a bridge is needed across a ditch between their houses. They work together and solve problems using trial and error. By sharing ideas and respecting one another's opinion, they make progress. They learn to be creative and how to work with the limited tools and materials at hand. They actually are learning the engineering principles of beam strength, beam deflections, dynamic loadings, and lateral stability. In addition, they also learn and practice some carpentry arts. They learn about safety and realize they could be hurt if they are not careful. They feel the pride of completing what they started out to accomplish.