when each agent has a varying number of friends chosen uniform randomly from (0, upper-limit-for-friends). Figure 2 gives a snapshot of the adult agents' friendship network. Figure 2 . Example of the adult agents' friend network Extended family network As discussed earlier the extended family network is crucial to accommodating orphans when there is no one left to look after them. Marriages are the way through which households get connected to the extended family network. Hence, the network may be perceived as overlapping clusters of households. At the start of the simulation households are initialized with no extended family networks. The households are nevertheless linked via the social neighbourhood shown in Figure 1. As the simulation proceeds and marriages occur, the extended family network grows. Alternatively, one can initialize the model with a pre-existing kinship network. In this case the model establishes extended family links to randomly chosen households, where the number of links assigned to each household is a parameter. Savings clubs ('stokvels') The social neighbours form the basis for informal savings clubs, known as stokvels. Members of a stokvel pay a mutually agreed sum into the club every month. The cumulative savings of the group are then rotated to each member of the group on a regular basis. After everyone has had their turn in receiving the contributions, the group may disband or start another cycle. Female household heads with higher literacy are usually the coordinators of these savings clubs ( Foster 2005 ; Verhoef 2001 ). We