① layout and circuit components position.
② in the show state--click to draw the shape--free curve--line according to the wiring (here also can choose ballpoint pen, watercolor stroke line)
③ students for the first time according to the circuit diagram line, more prone to error, when the student wiring error, when the comments modify, you can erase the line with the Eraser tool, and then reconnect. Is this so intuitive?
④ system default Line color is red, you can click Ink color to adjust shape color.