boolean appends(int asrc, int adst) { return !isEmpty() && adst == dst && asrc == (src + run);
boolean appends(Object asrc, Object adst) { return !isEmpty() && adst.equals(dst) && srcIsNum && asrc instanceof Number && ((Number) asrc).longValue() == (nsrc + run);
    boolean appends(int asrc, int adst) {      return !isEmpty() && adst == dst && asrc == (src + run);    }