Because i understand that all those topics that you mentioned began as ideas and then they became whole projects!So i am guessing that you probably do a lot of research...plus i tried making a video myself before and i found it extremly difficult to explain a phisical pnenomenom through a video so I appreciate your work and also thank you!
家用摄像头网上专卖店满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满意意满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满意意了我是我是我是我是我是我是我是非常满意！。