static S cal_simplifiedStructure(CirclesAndLines cal) {
  ret cal_simplifiedStructure(structure(cal));
}

static S cal_simplifiedStructure(S structure) {
  CirclesAndLines cal = cast unstructure(structure);
  for (Circle c : cal.circles) {
    c.x = roundToOneHundredth(c.x);
    c.y = roundToOneHundredth(c.y);
  }
  ret cal_structure_impl(cal);
}