#include <bits/stdc++.h>

using namespace std;

typedef long long ll;
typedef long double ld;

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

typedef vector<vi> vvi;
typedef vector<vll> vvll;

typedef pair<int, int> pii;
typedef pair<ll, ll> pll;

typedef vector<pii> vpii;
typedef vector<pll> vpll;

typedef vector<vpii> vvpii;
typedef vector<vpll> vvpll;

#define pb push_back
#define mp make_pair
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
#define sz(x) (int)(x).size()
#define fi first
#define se second

template<class T> bool ckmin(T &a, const T &b) {return a > b ? a = b, 1 : 0;}
template<class T> bool ckmax(T &a, const T &b) {return a < b ? a = b, 1 : 0;}

namespace debug {
    void __print(int x) {cerr << x;}
    void __print(long long x) {cerr << x;}
    void __print(double x) {cerr << x;}
    void __print(long double x) {cerr << x;}
    void __print(char x) {cerr << '\'' << x << '\'';}
    void __print(const string &x) {cerr << '\"' << x << '\"';}
    void __print(bool x) {cerr << (x ? "true" : "false");}

    template<typename T, typename V>
    void __print(const pair<T, V> &x) {cerr << '{'; __print(x.first); cerr << ','; __print(x.second); cerr << '}';}
    template<typename T>
    void __print(const T &x) {int f = 0; cerr << '{'; for(auto z : x) cerr << (f++ ? "," : ""), __print(z); cerr << "}";}
    void _print() {cerr << "]\n";}
    template <typename T, typename... V>
    void _print(T t, V... v) {__print(t); if(sizeof...(v)) cerr << ", "; _print(v...);}

#ifdef ljuba
#define dbg(x...) cerr << "LINE(" << __LINE__ << ") -> " << "[" << #x << "] = ["; _print(x)
#else
#define dbg(x...)
#endif
}

using namespace debug;

const char nl = '\n';

mt19937 rng(chrono::high_resolution_clock::now().time_since_epoch().count());

int mat[1000][1000];
int m, k;

bool moze(int n, const vi &v) {
    for(int i = 0; i < n; ++i) {
        for(int j = 0; j < n; ++j) {
            mat[i][j] = -1;
        }
    }

    vpii nz;
    for(int i = 0; i < k; ++i) {
        if(v[i]) {
            nz.pb({v[i], i+1});
        }
    }
    sort(all(nz));

    for(int i = 1; i < n; i += 2) {
        for(int j = 0; j < n; j += 2) {
            if(mat[i][j] != -1) continue;
            if(sz(nz) && nz.back().fi > 0) {
                nz.back().fi--;
                mat[i][j] = nz.back().se;
                if(nz.back().fi == 0)
                    nz.pop_back();
            }
        }
    }

    pii kasnije{-1, -1};

    if(sz(nz) && nz.back().fi > 0) {
        kasnije = nz.back();
        nz.pop_back();
    }

    dbg(kasnije);

    for(int i = 0; i < n; i += 2) {
        for(int j = 1; j < n; j += 2) {
            if(mat[i][j] != -1) continue;
            if(sz(nz) && nz.back().fi > 0) {
                nz.back().fi--;
                mat[i][j] = nz.back().se;
                if(nz.back().fi == 0)
                    nz.pop_back();
            }
        }
    }

    if(kasnije.fi != -1)
        nz.pb(kasnije);

    for(int i = 0; i < n; i += 2) {
        for(int j = 0; j < n; j += 2) {
            if(mat[i][j] != -1) continue;
            if(sz(nz) && nz.back().fi > 0) {
                nz.back().fi--;
                mat[i][j] = nz.back().se;
                if(nz.back().fi == 0)
                    nz.pop_back();
            }
        }
    }

    for(int i = 0; i < n; ++i) {
        for(int j = 0; j < n; ++j) {
            if(i % 2 == 1 && j % 2 == 1) continue;
            if(sz(nz)) {
                nz.back().fi--;
                mat[i][j] = nz.back().se;
                if(nz.back().fi == 0)
                    nz.pop_back();
            }
        }
    }

    return nz.empty();
}

void solve() {
    cin >> m >> k;
    vi v(k);
    for(auto &z : v) cin >> z;

    int mx = *max_element(all(v));
    int n = -1;
    for(int i = 1; ; ++i) {
        ll izraz = i * 1LL * ((i + 1) / 2);
        if(mx <= izraz) {
            ckmax(n, i);
            break;
        }
    }
    for(int i = 1; ; ++i) {
        ll izraz = i * 1LL * i;
        ll temp = i / 2;
        izraz -= temp * 1LL * temp;
        if(m <= izraz) {
            ckmax(n, i);
            break;
        }
    }

    while(!moze(n, v))
        ++n;

    cout << n << nl;
    for(int i = 0; i < n; ++i) {
        for(int j = 0; j < n; ++j) {
            if(mat[i][j] == -1) mat[i][j] = 0;
            cout << mat[i][j] << " ";
        }
        cout << nl;
    }
}

int main() {
    ios::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);

#ifdef ljuba
    freopen("input.txt", "r", stdin);
    freopen("output.txt", "w", stdout);
    freopen("error.txt", "w", stderr);
#endif

    int testCases = 1;
    cin >> testCases;
    while(testCases--)
        solve();

}