Your Internet startup needs a domain name.  Your market research guru
tells you that users tend to avoid sites with names that are hard to
type.  Thus, you must pick a name that is easy to type.  For your
research, you decide to use the idealized model of keyboards suggested
by Figure~\ref{fig:kbd}.  Note that the keys are perfectly aligned
both horizontally and vertically, unlike the skewed positioning of
keys in typical keyboards.  You decide to assign a {\em typing cost\/}
to each domain name (or any word, in general) based on the following
rules. .