4.  Flows:  Of resources over a network of nodes and connectors.  The nodes may be factories, and the connectors may be the transport routs for the flow of goods between factories.  This node (agent), connector (interactions), resource triad exists for other cas, such as the central nervous system with its nerve cells, their interconnections, and pulses, for food web interactions, for ecosystems etc.
>The flows through these cas networks vary over time, and nodes and connectors can appear and disappear as the agents adapt or fail to adapt.  Thus neither the flow nor the networks are fixed in time.  They are patterns that reflect changing adaptations as time elapses and experience accumulates.
>There are two properties of flows that are important to cas.  The first is the multiplier effect which occurs when one injects additional resources at some node.  This resource is passed from node to node, possibly being transformed along the way and produces a chain reaction.  For example, when you build a house, you pay the contractor who pays the workmen who buy food and so on through the economic network.  Thus for each dollar spent on the house, x amount of money flows through the economy, multiplying the effect of the original cost of the house.
>This multiplier effect is a major feature of networks and flow.  It arises regardless of the particular nature of the resource, networks or flows. 
>The multiplier effect is relevant when we want to estimate the effect of some new resource, or the effect of the diversion of some resource over a new path particularly evident when evolutionary changes occur, and it typically jeopardizes log-range predictions based on simple trends.
>The second property of flows that is important to cas is the recycling effect, the effect of cycles in the networks.
>The overall effect on cas of recycling increasing output can be striking.  The rain forest is rich in species and numbers and this diversity depends almost entirely on the forest's ability to capture and recycle critical resources.
>The forest departs from the traditional food chain where resources are passed upward to the top predator.  Instead, cycle after cycle traps the resources as they are used and reused before they finally make their way into the river system.