Operations:
Step 1: click the “Draw” button and select the “Polyline” command.
Step 2: specify the first point of line by dragging or clicking on the drawing area. When the finger lifts, the point achieved.
Step 3: adjust the first point or specify the next point of polyline. You could draw an arc segment by tapping “Arc” keyword behind command prompts;
Step 4: repeat step 3; adjust current point or specify next point. If there are two points or more than two on the polyline, it automatically adds a “Close” keyword. You could close the current polyline and end this command by tapping “Close” keyword.
Step 5: you could also cancel the last operation by tapping “Undo” keyword.
Step 6: Adjust current point or tap “✓” to confirm it.
Tips: In order to draw the Right Angle, a special effect occurs when the Angle is near vertical during the process of specifying the next point of a polyline.