Install instructions "triangle" strength not mentioned

[schneems]

In https://github.com/ploopyco/headphones/wiki/Part-4%3A-Headband it talks about a circle and square headband with different tension properties. There's also now a triangle headband that came with my kit. It seems like the difference is the curvature of the headbands. If that's true I'm guessing that it's now:

• Circle: Weakest
• Square: Medium
• Triangle: Strongest

Can you verify that's correct and update the wiki?

[shadow-absorber]