In the rest of this paper, we describe WOM and its implementation. We
have used WOM to implement Tow, a system for teaching labour-supply
economics: how people trade-off their preferences
between leisure time and the money earnt by selling that time to an
employer. Tow can be reached at
http://www6.ifs.org.uk/Tow/intro.htm . It is
still a prototype, and may contain some bugs: if you believe you have
found one, please report it via the IFS ``feedback'' form.