1, press ctrl+n, let's create a new sketchpad first, give the document a name, here it is called "circle and square", and click OK.

2. Select the ellipse tool in the left toolbar.

3. Click and drag the mouse on the drawing board to draw an ellipse;

This time, we can hold down the shift key, click and drag the mouse on the drawing board, and draw a perfect circle.

5. Hold down the shift+alt key this time, click and drag the mouse on the drawing board, and draw a perfect circle extending outward from the center point;