I was looking around for a project to implement on my mobile phone when I came across Joyce's lecture. First of all, I was very grateful that she uploaded the lecture she had worked hard on for free, and I was grateful that she kindly(?) taught me Android and Kotlin, which were somewhat unfamiliar to me as I was learning Python. In particular, the encouraging messages that appeared differently every day, which I assume were written automatically, were a source of strength. No matter what you learn, it is important to have a solid foundation, and unlike other lectures, Joyce's basic lecture was very thorough. Thanks to that, it was a great help for beginners to understand. Since the coding was uploaded about 2 years ago, I expected to have a lot of difficulty with the rapidly changing Android updates, but I had a little trouble because of deprecated functions. Fortunately, I was able to save a lot of time thanks to Gemini, which is built into Android Studio. Now that I've only coded it once, there's a long way to go. I have to repeat the learning process several times and make it a "must-have." Once again, I would like to thank Joyce for being a good guide.