A Children window typically presents the structure of a single node, that is, the dependencies among the children of the node. This portrays part of a level in the hierarchy, in a kind of horizontal ``slice''. The name of the parent node appears on the title bar.
Arcs or relationships connecting nodes in the graph are displayed as lines. Both nodes and arcs can be of various types; they are distinguished with customizable colors.
Arcs are also directed. An arc from source node A to destination node B is represented as a line from the bottom of node A to the top of node B. Node A is called a client of node B and node B is called a supplier of node A. The arc is an outgoing arc of node A and an incoming arc of node B. A node may have an arc going to itself, for a recursive relationship. You see this as a line from the bottom of a node to its top.
At the object level (of a C program), there are typically at least two kinds of nodes: data types and modules. A data type node, which represents an aggregate structure or user-defined type, is displayed as a node of type Data. A module node, which represents a function or procedure in the source code, is displayed as a node of type Module. The list example has two Data nodes and twelve Module nodes.
Also, within the object level (of a C program), there are typically at least three types of arcs: call, data, and composite. A call arc represents a function call from the source function to the destination function. A data arc represents one of the following: