This radical was developed from a circle with a central dot as the image of the sun. As you can hardly draw circles or dots with a brush, it became the current rectangular shape.
Image of a hand 一 forearm 丨 and pulse 丶. As a body part this is the forearm 肘. It was originally also the distance of one inch (Length: 1 ts'wun = 3.72 cm) from the hand's palm to the pulse. This also stood for a small amount. In the mnemonic, it is used as "skillful hand".
The app has many other functions, such as character selection according to difficulty, practice programs, handwriting recognition and success statistics!
