foreach w in (T( T(2), T(1), T(2,2), T(2,4), T(4,2), T(6,4,2) )){
   r:=primeWindows(PRIME_LIMIT,w);
   println("Successive primes (<=%,d) with deltas of %s (%,d groups):"
      .fmt(PRIME_LIMIT,w.concat(","),r.len()));
   println("   First group: %s;  Last group: %s\n"
      .fmt(r[0].concat(", "),r[-1].concat(", ")));
}