There should be a chapter in The Design of Everyday Things devoted to this dial.
@jameschip What...what does it...do?
@mensrea @liferstate @jameschip
I have actually used software that had a "Do" button

@RnDanger Was there a "Do not" button next to it?

@mensrea @liferstate @jameschip

@wonka @RnDanger @mensrea @liferstate @jameschip

"Do" button.
"Do not" button.
There is no "Try" button.