For the activities in this lesson and the next section, students will need strips cut from copies of the blackline masters. Prepare enough 1-inch strips with evenly-spaced holes so that every student gets 2 longer strips and 2 shorter strips. Put each set of strips in an envelope. Prepare one envelope for pairs of students. To prepare the strips and fasteners to be used throughout the unit, include 4 metal fasteners in each envelope.