Darn, I was hoping that they were created with some custom [plantuml] theme that I could steal, but it seems like they're [manually created] with inkscape.

[plantuml]: http://plantuml.com/

[manually created]: view-source:http://blog.mbrt.it/2016-12-01-ripgrep-code-review/crates.sv...

You could get close with graphiz.

  digraph G {
    "Ripgrep" -> "ignore"
    "ignore" -> "globset"
    "Ripgrep" -> "globset"
    "Ripgrep" -> "grep"
  }

http://www.webgraphviz.com

You could also set color, note I didn't do that in this example.

Plantuml is (I think) built on top of graphviz. In any case the syntax is extraordinarily similar. This[1] is similar to the first example:

  @startuml
  component ripgrep
  component ignore
  component globset
  component grep

  ripgrep --> ignore
  ignore --> globset
  ripgrep --> globset
  ripgrep --> grep
  @enduml

You can get the structure right, and easily, but those beautiful icons are not something that I know how to create, and the 90-degree turns are I think actually impossible.

The fact that it is so elegantly expressed in plantuml but it's still so ugly (by default) makes me really wish for a theme that's as nice as the hand-created diagram the author wrote.

[1]: http://www.plantuml.com/plantuml/uml/SoWkIImgAStDuU9ApiyjoCz...

Yes, I used Inkscape, but I'm not a designer, so I bet you can do something similar with a little bit of effort :) I'm not a fan of high level tools... they usually give a correct result, but a crappy look and feel...