#include <bits/stdc++.h>
using namespace std;
using ll=long long;
using ld=long double;
const ll ILL=2167167167167167167;
const int INF=2100000000;
#define rep(i,a,b) for (int i=(int)(a);i<(int)(b);i++)
#define all(p) p.begin(),p.end()
template<class T> using _pq = priority_queue<T, vector<T>, greater<T>>;
template<class T> ll LB(vector<T> &v,T a){return lower_bound(v.begin(),v.end(),a)-v.begin();}
template<class T> ll UB(vector<T> &v,T a){return upper_bound(v.begin(),v.end(),a)-v.begin();}
template<class T> bool chmin(T &a,T b){if(a>b){a=b;return 1;}else return 0;}
template<class T> bool chmax(T &a,T b){if(a<b){a=b;return 1;}else return 0;}
template<class T> void So(vector<T> &v) {sort(v.begin(),v.end());}
template<class T> void Sore(vector<T> &v) {sort(v.begin(),v.end(),[](T x,T y){return x>y;});}
bool yneos(bool a,bool upp=0){if(a){cout<<(upp?"YES\n":"Yes\n");}else{cout<<(upp?"NO\n":"No\n");}return a;}
template<class T> void vec_out(vector<T> &p,int ty=0){
    if(ty==2){cout<<'{';for(int i=0;i<(int)p.size();i++){if(i){cout<<",";}cout<<'"'<<p[i]<<'"';}cout<<"}\n";}
    else{if(ty==1){cout<<p.size()<<"\n";}for(int i=0;i<(int)(p.size());i++){if(i) cout<<" ";cout<<p[i];}cout<<"\n";}}
template<class T> T vec_min(vector<T> &a){assert(!a.empty());T ans=a[0];for(auto &x:a) chmin(ans,x);return ans;}
template<class T> T vec_max(vector<T> &a){assert(!a.empty());T ans=a[0];for(auto &x:a) chmax(ans,x);return ans;}
template<class T> T vec_sum(vector<T> &a){T ans=T(0);for(auto &x:a) ans+=x;return ans;}
int pop_count(long long a){int res=0;while(a){res+=(a&1),a>>=1;}return res;}



void solve();
// CYAN / FREDERIC
int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);

    int t = 1;
    cin >> t;
    rep(i, 0, t) solve();
}

void solve() {
    int N, M;
    cin >> N >> M;
    if ((N * M) % 8 || min(N, M) == 1) {
        cout << "-1\n";
        return;
    }
    vector<string> table1 = {
            "111",
            "221",
            "233",
            "234",
            "534",
            "544",
            "556",
            "666"
    };
    vector<string> table2 = {
            "11",
            "12",
            "12",
            "22"
    };
    auto rev = [&](vector<string> a) -> vector<string> {
        vector<string> res(a[0].size());
        rep(i, 0, a.size()) rep(j, 0, a[0].size()) {
                res[j] += a[i][j];
            }
        return res;
    };
    vector ans(N, vector<int>(M));
    int U = 0;
    auto f = [&](int sx, int sy, int len_x, int len_y) -> void {
        auto table = table1;
        if (len_x == 3) table = rev(table1);
        if (len_x == 4) table = table2;
        if (len_x == 2) table = rev(table2);
        rep(i, 0, len_x) rep(j, 0, len_y) {
                ans[i + sx][j + sy] = U + table[i][j] - '0';
            }
        U += (len_x * len_y) / 4;
    };
    if (N % 2 == 0 && M % 4 == 0){
        rep(i, 0, N / 2) rep(j, 0, M / 4) f(i * 2, j * 4, 2, 4);
    }
    else if (N % 4 == 0 && M % 2 == 0){
        rep(i, 0, N / 4) rep(j, 0, M / 2) f(i * 4, j * 2, 4, 2);
    }
    else if (N % 8 == 0){
        rep(i, 0, N / 4) rep(j, 0, M / 2 - 1) f(i * 4, j * 2 + 3, 4, 2);
        rep(i, 0, N / 8) f(i * 8, 0, 8, 3);
    }
    else{
        rep(i, 0, N / 2 - 1) rep(j, 0, M / 4) f(i * 2 + 3, j * 4, 2, 4);
        rep(j, 0, M / 8) f(0, j * 8, 3, 8);
    }
    cout << (N * M ) / 4 << "\n";
    rep(i, 0, N){
        vec_out(ans[i]);
    }
}