This truncated diagram provides an example of how to read the solid red relationship lines to move in one direction:

The first class specification is Diagram.

The second is that contain Symbols.

The third Relation/Class specification is defined by Definitions.

The fourth Relation/Class specification (assuming a global model) is uses Definitions.

The fifth and last Relation/Class specification is that are instances of (is a) Definition.

When writing a report, you must pick an object (like a diagram) as a starting point and travel only in the direction indicated by the arrows, always staying with the same color-coded line. Therefore, if you choose to travel along a red-labeled arrow, you cannot specify a relation between objects that are displayed on a line ending with a blue-labeled arrow.