  We describe a model for the colloidal glass transition that is based on
Feynman's theory for the $\lambda$-transition in liquid helium. Our model
essentially counts the number of configurations of dynamic loops, strings or
clusters of different sizes, and determines the glass transition volume
fraction $\phi_{g}$ from the distribution of these heterogeneities. Since
confinement restricts the available number of configurations for these loops,
strings and clusters, its effect on $\phi_{g}$ can also be calculated in a
relatively straightforward manner.
