Child B comes up, holds his hands out to touch both ends of the course on the chalkboard, and then moves over to the adjacent course to compare them. Watching this, Child C says, "No way. The distance between your hands is getting shorter. You have to do it right." Child B tries several times to fix it, but the results are· still imprecise. Child D then says, "Teacher, what if you were to check it instead by using your finger like an. inchworm?" They tried this too, but they realized there was a problem when the distance between their fingers changed during the process.
In this way, the students exchanged ideas with one another, determined that they need something whose width would not change, and came up with the idea of using the strips of paper used for the Janken Race. Thus; the lanes were adjusted to the same length.