2ariel.ulp
output("/tmp/ariel.xml", "wt") {
  board(B) {
    printf("<?xml version=\"1.0\" encoding=\"UTF8\"?>\n");
    printf("<board name=\"%s\">\n",B.name);
    B.signals(S) {
      printf("\t<signal name=\"%s\">\n",S.name);
      S.wires(W){
        if (W.layer==1)
          printf("\t\t<wire layer=%d x1=%d x2=%d y1=%d y2=%d/>\n", W.layer, W.x1, W.x2, W.y1, W.y2 );
      }
      printf("\t</signal>\n");  
    }
    printf("</board>\n");
  }
}