-`p1Style` : The end-cap style of the point `p1`. The value must be `"CAP_BUTT"`, `"CAP_CIRCLE"` or `"CAP_SPHERE"`. The default value is `"CAP_CIRCLE"`.
-`p2Style` : The end-cap style of the point `p2`. The value must be `"CAP_BUTT"`, `"CAP_CIRCLE"` or `"CAP_SPHERE"`. The default value is `"CAP_CIRCLE"`.
-`$fa`, `$fs`, `$fn` : Used by the `circle` or `sphere` module internally. Check [the circle module](https://en.wikibooks.org/wiki/OpenSCAD_User_Manual/Using_the_2D_Subsystem#circle) or [the sphere module](https://en.wikibooks.org/wiki/OpenSCAD_User_Manual/Primitive_Solids#sphere) for more details.