Sequence Diagram (BlockDiag)
SeqDiag (part of Blockdiag) lets you describe interactions between participants over time as text, and automatically renders them as sequence diagrams - the kind used in UML to show message passing between objects or systems.
seqdiag {
browser -> webserver [label = "GET /seqdiag/svg/base64"];
webserver -> processor [label = "Convert text to image"];
webserver <-- processor;
browser <-- webserver;
}
