Students appreciate the pervasive use and power of reasoning as a part of mathematics.
This activity has to do with a branch of mathematics called topology. In topology, the objects are defined by features that persist even when objects are stretched, shrunk or dented. Size and shape are allowed to vary, but holes or tears cannot be made. To solve the puzzle one must be somewhat creative and realize that the shirt can be turned wrong side out through the sleeve holes as well as through the neck and waist holes. Challenge the pair to have the student take off the shirt, turn it inside-out and put it back on again without removing or disconnecting the string.