In some graphics programs there are corner radius values that are cornerRadiusX and cornerRadiusY. I have even seen topLeftRadiusX and topLeftRadiusY plus six more properties; 2 properties per corner .
For example there is this FXG / SVG code,
<s:Rect id="lowlight" left="1" right="1" top="1" bottom="1" topLeftRadiusX="4" topRightRadiusX="4">
</s:Rect>
I've never seen topLeftRadiusX and topLeftRadiusY used together but then again I've never seen them used very much at all.
What are they for and how do they affect the graphic?