Drag to a rectangular canvas, resized 260x260, select the shape
Screen shot 2019-06-04 15.35.56.png
Select the round notch
Screen shot 2019-06-04 15.37.00.png
Gap adjustment 1/4
Screen shot 2019-06-04 15.38.14.png
A canvas to drag oval
Screen shot 2019-06-04 15.41.28.png
Size is set to 230x230
Screen shot 2019-06-04 15.42.22.png
Click to select the first round notched, click to select the internal circular.
Screen shot 2019-06-04 15.46.14.png
Then select the style removed
Screen shot 2019-06-04 15.46.52.png
The two shape change into a new ring. Set the background color
Screen shot 2019-06-04 15.48.07.png
In drag two rectangular, semicircular converted into
Screen shot 2019-06-05 16.39.32.png
Size 15x10, and then rotated to a suitable angle
Screen shot 2019-06-05 16.41.08.png
They are now two semicircles. merge
Screen shot 2019-06-05 16.47.49.png
Selected original 237 degrees rotation
Screen shot 2019-06-05 16.51.40.png
The above steps are repeated two rectangular drag
Screen shot 2019-06-05 16.59.26.png
Select the two rectangles, remove
Screen shot 2019-06-05 17.01.09.png
In drag the two rectangles, select the semicircle. Suitable combined rotation angle
Screen shot 2019-06-05 17.11.42.png
Drag in a circle, and the width of the line is set to 0 for all components,
Screen shot 2019-06-05 17.15.07.png