Node-Edge Relationships
Each edge is associated with an ordered collection of two nodes: a starting node and an ending node
- When an edge forms a loop, its starting and ending nodes are the same node
Each node is associated with an unordered collection of zero or more connected edges
- In 2D, the connected edges are ordered counterclockwise around the node (starting with an arbitrary edge)
- In 3D, the connected edges cannot, in general, be ordered, since they can connect to the node from any direction in 3D space