User talk:123.231.121.132

November 2015
Hello, I'm Érico. I wanted to let you know that I undid one or more of your recent contributions to Speed of light ‎ because it did not appear constructive. If you would like to experiment, please use the sandbox. If you think I made a mistake, or if you have any questions, you can leave me a message on my talk page. Thanks. Érico  (msg)  06:16, 7 November 2015 (UTC)
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