User talk:121.7.164.26

September 2021
Hello, I'm Jack Frost. I wanted to let you know that I reverted one of your recent contributions—specifically this edit to Total internal reflection—because it 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. Jack Frost (talk) 07:18, 19 September 2021 (UTC)