A. Select the Top viewport and click the Maximize Viewport Toggle button on the bottom right of the screen. 
Zoom in a bit.
Change to ciruclar selection and select the polygons as shown in the following image:
A. Select the Top viewport and click the Maximize Viewport Toggle button on the bottom right of the screen. |
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| B. Click the Shrink button two times. |
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| C. Enable the Use Soft Selection option in the Soft Selection section of the Modify tab and scale down the polygons on the X and Y axis as displayed below: |
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