Use UserDefaults or @AppStorage

Maybe you need to save the key data of color and angle, and then read and instantiate it from userdefalts when necessary, such as double of angle.

It's very bad. I found that if the data read by geometryreader is captured by a func but not used, this problem will occur. Memory occupies 30G quickly, and the hard disk reads and writes a lot. Even if Xcode is turned off, it still doesn't help. You must to click to turn off by yourself！

The width ratio of iPad is 4:3, so you must set such a ratio, such as 600:450, and if you don't, there will be something wrong with the display.