#include <bits/stdc++.h>
using namespace std;
void solve() {
  long long int n, i, t, j, p, q, a, b, m;
  cin >> t;
  while (t--) {
    cin >> n >> m;
    string s[n];
    bool ck = true;
    ;
    p = (n * m);
    if (p % 2 == 0)
      a = (p / 2) - 1;
    else
      a = p / 2;
    for (i = 0; i < n; i++) {
      for (j = 0; j < m; j++) {
        if (!ck && a) {
          s[i] += "W";
          a--;
          ck = true;
          continue;
        } else {
          s[i] += "B";
          ck = false;
          continue;
        }
      }
    }
    if (p % 2 == 0) {
      s[n - 2][m - 2] = 'W';
      s[n - 2][m - 1] = 'B';
    }
    for (i = 0; i < n; i++) cout << s[i] << endl;
  }
  return;
}
int main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  solve();
  return 0;
}
