#pragma GCC optimize("O3")
#pragma GCC optimize("unroll-loops")
#include <iostream>
#include <vector>
#include <algorithm>
#include <cmath>
#include <string>
#include <queue>
#include <stack>
#include <set>
#include <map>
#include <array>
#include <iomanip>
#include <utility>
#include <tuple>
#include <functional>
#include <bitset>
#include <cassert>
#include <complex>
#include <stdio.h>
#include <time.h>
#include <numeric>
#include <random>
#include <unordered_set>
#include <unordered_map>
#define all(a) (a).begin(), (a).end()
#define rep(i, n) for (ll i = 0; i < (n); i++)
#define req(i, a, b) for (ll i = (a); i < (b); i++)
#define pb push_back
#define debug(x) cerr << __LINE__ << ' ' << #x << ':' << (x) << '\n'
#define debug2(x, y) cerr << __LINE__ << ' ' << #x << ':' << (x) << ',' << #y << ':' << (y) << '\n'
#define debug3(x, y, z) cerr << __LINE__ << ' ' << #x << ':' << (x) << ',' << #y << ':' << (y) << ',' << #z << ':' << (z) << '\n'
using namespace std;
typedef long long ll;
typedef unsigned int uint;
typedef unsigned long long ull;
typedef long double ld;
template<class T> using P = pair<T, T>;
template<class T> using pri_l = priority_queue<T>;
template<class T> using pri_s = priority_queue<T, vector<T>, greater<T>>;
constexpr int inf = 1000000010;
constexpr int inf2 = 2000000010;
constexpr ll INF = 1000000000000000010;
constexpr ll INF4 = 4000000000000000010;
constexpr int mod1e9 = 1000000007;
constexpr int mod998 = 998244353;
constexpr ld eps = 1e-12;
constexpr ld pi = 3.141592653589793238;
constexpr ll ten(int n) { return n ? 10 * ten(n - 1) : 1; };
int dx[] = { 1,0,-1,0,1,1,-1,-1,0 }; int dy[] = { 0,1,0,-1,1,-1,1,-1,0 };
ll mul(ll a, ll b) { return (b != 0 && a > INF / b ? INF : a * b); }
void fail() { cout << "-1\n"; exit(0); } void no() { cout << "No\n"; exit(0); }
template<class T> void er(T a) { cout << a << '\n'; exit(0); }
template<class T, class U> inline bool chmax(T& a, const U& b) { if (a < b) { a = b; return true; } return false; }
template<class T, class U> inline bool chmin(T& a, const U& b) { if (a > b) { a = b; return true; } return false; }
template<class T> istream& operator >>(istream& s, vector<T>& v) { for (auto& e : v) s >> e; return s; }
template<class T> ostream& operator <<(ostream& s, const vector<T>& v) { for (auto& e : v) s << e << ' '; return s; }
template<class T, class U> ostream& operator << (ostream& s, const pair<T, U>& p) { s << p.first << ' ' << p.second; return s; }

struct fastio {
	fastio() {
		cin.tie(0); cout.tie(0);
		ios::sync_with_stdio(false);
		cout << fixed << setprecision(20);
		cerr << fixed << setprecision(20);
	}
}fastio_;

namespace rdv {
	random_device seed_gen;
	mt19937_64 engine(seed_gen());
	ll rnum(ll r) { return engine() % r; } // [0, r)
	ll rnum(ll l, ll r) { return rnum(r - l) + l; } // [l, r)
	ll rng(ll l, ll r) { return rnum(l, r + 1); } // [l, r]
	double rng01() { return engine() * pow(2, -64); }
	template<class T> void shuf(vector<T>& v) { shuffle(all(v), engine); }
	void shuf(string& s) { shuffle(all(s), engine); }
}

using namespace rdv;

template<class T> vector<int> compress(vector<T> v) {
	int n = v.size();
	vector<T> tmp = v;
	sort(tmp.begin(), tmp.end());
	tmp.erase(unique(tmp.begin(), tmp.end()), tmp.end());
	vector<int> res(n);
	for (int i = 0; i < n; i++) res[i] = lower_bound(tmp.begin(), tmp.end(), v[i]) - tmp.begin();
	return res;
}

#include <atcoder/all>
using namespace atcoder;

constexpr ll mod = mod998;
using mint = static_modint<mod>;

istream& operator >>(istream& s, mint& m) { ll y; s >> y; m = y; return s; }
ostream& operator <<(ostream& s, mint& m) { return s << m.val(); }
ostream& operator <<(ostream& s, const vector<mint>& v) { for (auto& e : v) s << e.val() << ' '; return s; }

vector<mint> fac, inv, facinv;

void modcalc(int n) {
	fac.resize(n); inv.resize(n); facinv.resize(n);
	fac[0] = 1; fac[1] = 1; inv[1] = 1;
	facinv[0] = 1; facinv[1] = 1;
	for (ll i = 2; i < n; i++) {
		fac[i] = fac[i - 1] * i;
		inv[i] = -inv[mod % i] * (mod / i);
		facinv[i] = facinv[i - 1] * inv[i];
	}
}

mint comb(ll n, ll k) {
	if (n < 0 || k < 0 || n < k) return 0;
	return fac[n] * facinv[k] * facinv[n - k];
}

mint perm(ll n, ll k) {
	if (n < 0 || k < 0 || n < k) return 0;
	return fac[n] * facinv[n - k];
}

mint hom(ll n, ll k) {
	if (n < 0 || k < 0 || n == 0 && k > 0) return 0;
	if (n == 0 && k == 0) return 1;
	return fac[n + k - 1] * facinv[k] * facinv[n - 1];
}

int main() {

	bool DEBUG = false;

	int N = DEBUG ? 10 : 300;

	int TEST = 1;
	cin >> TEST;
	while (TEST--) {
		vector<P<int>> a(4);
		rep(i, 4) {
			if (DEBUG) {
				while (1) {
					a[i].first = rng(3, 7);
					a[i].second = rng(3, 7);
					bool good = true;
					rep(j, i) {
						if (a[i].first == a[j].first) good = false;
						if (a[i].second == a[j].second) good = false;
					}
					if (good) break;
				}
			}
			else {
				cin >> a[i].first >> a[i].second;
				a[i].first += N / 2; a[i].second += N / 2;
			}
		}

		rep(i, 4) rep(j, i) {
			assert(a[i].first != a[j].first);
			assert(a[i].second != a[j].second);
		}

		if ((a[0].first + a[0].second + a[1].first + a[1].second) % 2 == 1) {
			// パリティが合ってないと一生合わない
			cout << "-1\n";
			continue;
		}

		if (a[0].first > a[1].first) {
			swap(a[0], a[1]);
			swap(a[2], a[3]);
		}

		if (a[0].second + 1 == a[1].second) {
			int x = a[0].first - N / 2, y = a[0].second - N / 2;
			if (!DEBUG) {
				cout << 5 << '\n';
				cout << x - 1 << ' ' << y << '\n';
				cout << x << ' ' << y - 1 << '\n';
				cout << x + 1 << ' ' << y << '\n';
				cout << x + 1 << ' ' << y + 2 << '\n';
				cout << x + 2 << ' ' << y + 1 << '\n';
			}
			continue;
		}

		if (a[0].second - 1 == a[1].second) {
			int x = a[0].first - N / 2, y = a[0].second - N / 2;
			if (!DEBUG) {
				cout << 5 << '\n';
				cout << x - 1 << ' ' << y << '\n';
				cout << x << ' ' << y - 1 << '\n';
				cout << x << ' ' << y + 1 << '\n';
				cout << x + 1 << ' ' << y - 2 << '\n';
				cout << x + 2 << ' ' << y - 1 << '\n';
			}
			continue;
		}

		auto bfs = [&](int sx, int sy, int gx, int gy, vector<vector<int>>& v) -> int {
			vector D(N + 1, vector<int>(N + 1, inf));
			D[sx][sy] = 0;
			queue<P<int>> que;
			que.push({ sx, sy });
			while (!que.empty()) {
				auto& [x, y] = que.front(); que.pop();
				rep(d, 4) {
					int nx = x + dx[d], ny = y + dy[d];
					if (0 <= nx && nx <= N && 0 <= ny && ny <= N && v[nx][ny] != -1 && D[nx][ny] == inf) {
						bool bad = false;
						rep(i, 4) if (a[i].first == nx && a[i].second == ny) bad = true;
						if (!bad) {
							D[nx][ny] = D[x][y] + 1;
							que.push({ nx, ny });
						}
					}
				}
			}
			return D[gx][gy];
		};

		if (DEBUG) rep(i, 4) debug(a[i]);
		vector<P<int>> ans;

		// Alice を x = 1, Bob を x = N - 1 に持っていく

		vector v(N + 1, vector<int>(N + 1)); // use : 1, ng : -1
		rep(i, 4) v[a[i].first][a[i].second] = 1;

		// rollback dfs

		auto sol = [&](bool is_Alice) -> vector<P<int>> {

			vector<P<int>> path;
			bool fin = false;

			if (is_Alice) path = { a[0] };
			else path = { a[1] };

			auto dfs = [&](auto dfs, int x, int y, int px, int py, bool is_Alice) -> void {
				if (x == (is_Alice ? 1 : N - 1)) fin = true;
				if (fin) return;
				vector<P<int>> cand;
				// debug2(x, y);
				rep(d, 4) {
					bool bad = false;
					int nx = x + dx[d], ny = y + dy[d];
					if (ny <= 2 or ny >= N - 2) continue;
					rep(i, 4) if (nx == a[i].first && ny == a[i].second) bad = true;
					if (bad) continue;
					if (v[nx][ny] == -1) continue;
					if (nx == px && ny == py) continue;
					if (!is_Alice) if (abs(nx - a[0].first) + abs(ny - a[0].second) <= 1) continue;
					if (is_Alice) if (abs(nx - a[1].first) + abs(ny - a[1].second) <= 1) continue;
					if (is_Alice) {
						if (abs(nx - a[2].first) + abs(ny - a[2].second) <= 1) continue;
						if (abs(nx - a[3].first) + abs(ny - a[3].second) == 1) {
							cand.clear();
							cand.push_back({ nx, ny });
							break;
						}
					}
					if (!is_Alice) {
						if (abs(nx - a[3].first) + abs(ny - a[3].second) <= 1) continue;
						if (abs(nx - a[2].first) + abs(ny - a[2].second) == 1) {
							cand.clear();
							cand.push_back({ nx, ny });
							break;
						}
					}
					cand.push_back({ nx, ny });
				}
				// debug(cand);
				sort(all(cand), [&](P<int> p0, P<int> p1) {
					return is_Alice ? (p0 < p1) : (p0 > p1);
				});
				for (auto& [nx, ny] : cand) {
					path.push_back({ nx, ny });
					v[nx][ny] = 1;
					dfs(dfs, nx, ny, x, y, is_Alice);
					if (fin) break;
					path.pop_back();
					v[nx][ny] = 0;
				}
			};

			if (is_Alice) dfs(dfs, a[0].first, a[0].second, -1, -1, true);
			else dfs(dfs, a[1].first, a[1].second, -1, -1, false);

			return path;
		};

		auto p0 = sol(1); int s0 = ssize(p0);
		rep(i, s0 - 1) {
			auto& [x, y] = p0[i];
			rep(d, 4) {
				int nx = x + dx[d], ny = y + dy[d];
				if (v[nx][ny] == 0) v[nx][ny] = -1;
			}
		}

		auto p1 = sol(0); int s1 = ssize(p1);
		rep(i, s1 - 1) {
			auto& [x, y] = p1[i];
			rep(d, 4) {
				int nx = x + dx[d], ny = y + dy[d];
				if (v[nx][ny] == 0) v[nx][ny] = -1;
			}
		}

		int y0 = p0.back().second, y1 = p1.back().second;
		int len = y0 + y1 + N;
		// assert((s0 + s1 + len) % 2 == 0);

		// debug(1);
		int d0 = bfs(a[0].first, a[0].second, p0.back().first, p0.back().second, v);
		int d1 = bfs(a[1].first, a[1].second, p1.back().first, p1.back().second, v);
		// debug2(p0, p1);
		// debug2(d0, d1);

		while (d0 < d1) {
			auto& [x, y] = p0.back();
			if (y == 1) p0.push_back({ x + 1, y });
			else p0.push_back({ x, y - 1 });
			d0++;
		}
		while (d0 > d1) {
			auto& [x, y] = p1.back();
			if (y == 1) p1.push_back({ x - 1, y });
			else p1.push_back({ x, y - 1 });
			d1++;
		}

		while (p0.back().first != p1.back().first) {
			auto& [x0, y0] = p0.back();
			auto& [x1, y1] = p1.back();
			if (y0 == 1) p0.push_back({ x0 + 1, y0 });
			else p0.push_back({ x0, y0 - 1 });
			if (y1 == 1) p1.push_back({ x1 - 1, y1 });
			else p1.push_back({ x1, y1 - 1 });
		}

		rep(i, ssize(p0)) v[p0[i].first][p0[i].second] = 1;
		rep(i, ssize(p1)) v[p1[i].first][p1[i].second] = 1;

		rep(i, ssize(p0) - 1) {
			auto& [x, y] = p0[i];
			// debug2(x, y);
			rep(d, 4) {
				int nx = x + dx[d], ny = y + dy[d];
				if (v[nx][ny] == 0) v[nx][ny] = -1;
			}
		}

		rep(i, ssize(p1) - 1) {
			auto& [x, y] = p1[i];
			// debug2(x, y);
			rep(d, 4) {
				int nx = x + dx[d], ny = y + dy[d];
				if (v[nx][ny] == 0) v[nx][ny] = -1;
			}
		}

		rep(i, N + 1) rep(j, N + 1) if (v[i][j] == -1) ans.push_back({ i - N / 2, j - N / 2 });

		if (DEBUG) {
			vector C(N + 1, vector<char>(N + 1, '.'));
			rep(i, N + 1) rep(j, N + 1) if (v[i][j] == -1) C[i][j] = 'X';
			rep(i, 4) {
				// assert(C[a[i].first][a[i].second] == '.');
				C[a[i].first][a[i].second] = 'A' + i;
			}

			int X = p0.back().first, Y = p0.back().second;
			assert(X == p1.back().first); assert(Y == p1.back().second);
			int D0 = bfs(a[0].first, a[0].second, X, Y, v);
			int D1 = bfs(a[1].first, a[1].second, X, Y, v);
			rep(i, N + 1) {
				rep(j, N + 1) cerr << C[i][j];
				cerr << '\n';
			}
			debug2(D0, D1);
			assert(D0 == D1);
		}

		else {
			int sz = ssize(ans);
			assert(sz <= 4000);
			cout << sz << '\n';
			for (auto& [x, y] : ans) cout << x << ' ' << y << '\n';
		}
	}

}