Make images that represent TDD process more circular like in GOOS?

[martinmoene]

When talking about a circular TDD process flow, figures that show it in a not-so-much-circular fashion may look a little bit odd.

See e.g. figures of Growing Object-Oriented Software Guided by Tests.

[grzesiek-galezowski]

I like the pictures and appreciate that Nat and Steve made them available under permissive license, however, I don't think they will make others for me, e.g. ones using the modified terminology.

The only limiting factor for me is that I would like the images to be generated from a textual representation to track changes. I'm currently using dot, graphviz and plantuml for images. If there's a way to make these tools produce a more circular diagram or another tool that could generate it from a textual representation, this would be perfect.