D.cpp

#include <bits/stdc++.h>

using namespace std;

#ifndef HELLO_PEOPLE
#define cerr if(0) cout
#endif

using ll = long long;
using ld = long double;

#define all(v) (v).begin(), (v).end()
#define X first
#define Y second

// magic
template<class T> struct Nit { T _v, _s; Nit(T v, T s) : _v(v), _s(s) {} operator T &() { return _v; } T operator *() const { return _v; } Nit &operator++() { _v += _s; return *this; } bool operator!=(Nit &a) { return (_s > 0 ? _v < a._v : _v >= a._v); } }; template<class T = int> struct range { T _b, _e, _s; range(T e) : _b(0), _e(e), _s(1) {} range(T b, T e, T s = 1) : _b(b), _e(e), _s(s) {} Nit<T> begin() { return Nit<T>(_b, _s); } Nit<T> end() { return Nit<T>(_e, _s); } }; template<class T = int> struct rrange : range<T> { rrange(T e, T b, T s = 1) : range<T>(e, b, -s) {} rrange(T e) : range<T>(e, 0, -1) {} };  template<int D, class T> struct vec : public vector<vec<D - 1, T>> { template<class... Args> vec(int n = 0, Args... a) : vector<vec<D - 1, T>>(n, vec<D - 1, T>(a...)) {} }; template<class T> struct vec<1, T> : public vector<T> { vec(int n = 0, T const &val = T()) : vector<T>(n, val) {} };

// now start
ll constexpr INF = 1e14;


int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);

    auto &&run_case = []() {
        int n, k;
        cin >> n >> k;

        vector<int> r(n);
        int d = k / n;
        fill(all(r), d);
        int rm = k % n;
        for (auto i : range<>(rm)) {
            r[i]++;
        }

        vec<2, int> mp(n, n);
        int j = 0;
        for (auto i : range<>(n)) {
            for (auto x : range<>(r[i])) {
                j = (j + 1) % n;
                mp[i][j] = 1;
            }
        }

        vector<int> c(n);
        for (auto x : range<>(n)) {
            for (auto i : range<>(n)) {
                c[j] += mp[i][x];
            }
        }

        cout << !!rm * 2 << '\n';
        for (auto i : range<>(n)) {
            for (auto x : range<>(n)) {
                cout << mp[i][x];
            }
            cout << '\n';
        }
    };

    int tc;
    cin >> tc;
    while (tc--) run_case();
    return 0;
}