res/values/borders.xml

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <!-- Border shapes -->
    <!-- All shapes must be drawn in a 100 by 100 square -->
    <string name="circular_border" translatable="false">M50,0 A50,50,0,1,1,50,100 A50,50,0,1,1,50,0</string>
</resources>