This theme is discontinued and possibly out of date.
This is a legacy page. Twenty Ten Tri is a child theme for Twenty Ten. It adds a second sidebar to the left of the content, giving your site a three column decide. You need to have the original Twenty Ten theme in your themes folder for Twenty Ten Tri to work.
Twenty Ten Tri first appeared as an example in the Smashing WordPress Themes: Making WordPress Beautiful book.
This child theme is fully GPL compliant and so on, provided as is. Do what you wish with it, and enjoy.
Twenty Ten user making the switch?
If you’re a current Twenty Ten user making the switch to Twenty Ten Tri, then you should make sure that you update your Media settings accordingly. The content width for Twenty Ten Tri is 420 pixels, so make sure you change that. You might also want to regenerate your images using the excellent Regenerate Thumbnails plugin – just change your Media settings first.