December 2013
edit
Hello, I'm Mark Arsten. I wanted to let you know that I undid one of your recent contributions, such as the one you made with this edit to Coordinate rotations and reflections, because it didn’t appear constructive to me. If you think I made a mistake, or if you have any questions, you can leave me a message on my talk page. Thanks. Mark Arsten (talk) 00:32, 18 December 2013 (UTC)
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