User talk:156.212.107.76

May 2020
Hello, I'm Amkgp. An edit that you recently made to Longitudinal wave seemed to be a test and has been removed. If you want to practice editing, please use the sandbox. If you think a mistake was made, or if you have any questions, you can leave me a message on my talk page. Thanks! Amkgp (talk) 20:44, 4 May 2020 (UTC)
 * If this is a shared IP address, and you did not make the edits referred to above, consider creating an account for yourself or logging in with an existing account so that you can avoid further irrelevant notices.