Each student should be given a task or job in the group. One student obtains all the materials, one draws the design, one cuts the materials, and all help assemble.
Two class periods.
Day 1 The students are shown the materials from what they have available and must design the shoes. with only those materials in mind.
Day 2 The students are to build their shoes to match their design. Once completed the testing begins. Testing can be done in the form of a competition.