#include <bits/stdc++.h>

#define rep(i, l, r) for(int i = (int)l; i < (int)r; i++)
#define all(v) v.begin(), v.end()
#define sz(v) (int)v.size()
using namespace std;

using ll = long long;
using pll = pair<ll, ll>;
using pii = pair<int, int>;
using ld = long double;

typedef vector<ll> vl;
typedef vector<int> vi;

template<class T>
void out(const vector<T> &v) {
    for (auto x: v)cout << x << " ";
    cout << endl;
}

const ll linf = 1e15 + 10;

void solve() {
    
    int n, k;cin >> n >> k;
    if (n % 2 == 1 || k >= n) {
        cout << "Impossible" << endl;
        return;
    }

    rep(x, 1, n) {
        rep(i, 0, n){
            if (i)cout << " ";
            cout << 1 + (i ^ x);
        }
        cout << endl;
    }
}

int main() {


    ios::sync_with_stdio(false);
    cin.tie(nullptr);

    int T; cin >> T;
    while(T--) {
        solve();
    }
    
}