User talk:106.197.23.31

January 2019
Hello, I'm Classicwiki. I wanted to let you know that one or more of your recent contributions to Center of mass have been undone because they did not appear constructive. If you would like to experiment, please use the sandbox. If you have any questions, you can ask for assistance at the Help Desk. Thanks. Classicwiki (talk) If you reply here, please ping me. 04:57, 20 January 2019 (UTC)