I haven't really done a lot with shape scripts, but from looking at the documentation I've come up with the following. (Which I admit isn't perfect)
shape main
{
// draw a dashed line
noshadow=true;
setlinestyle("SOLID");
moveto(0,0);
lineto(100,0);
setorigin("CENTER",0,0);
addsubshape("assembly", 15, 15);
shape assembly
{
scalable="false";
ellipse(3,3,12,12);
arc(0,0,15,15,7,0,7,15);
}
}