Thank you, @lobbyvzla, for your good advice. I like your posts, your drawings, and voted up to them. Can you take look at mypost https://hive.blog/hive-194913/@olgavita/does-anybody-know-how-this-phenomenon-is-called and some previous posts which were mot successful. Maybe you can tell me what is wrong with them? Of course, only if you have time for that. Thank you.