#include <bits/stdc++.h>
using namespace std;

#define int long long
#define double long double

const double PI = 3.14159265358979323846;
const int INF = 9223372036854775807/2; //\!!!!!!!!!!!!!!!!!!!!!!
const int mod = INF;

mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());

int fastPow(int b, int e){int r = 1;while(e){if(e%2 == 1){r*=b;r%=mod;}b*=b;b%=mod;e/=2;}return r;}
int gcd(int a, int b){ if(a%b == 0) return b; else return gcd(b, a%b);}
int sign(int a){if(a < 0){ return -1;}if(a == 0) {return 0;}return 1;}
bool isPrime(int a){if(a <= 1) {return false;}int f = a;for(int i = 2; i*i<=f; i++){if(a%i == 0){return false;}}return true;}
int toInt(string s){int tot = 0;for(int i = s.size()-1; i >= 0; i--){tot+=((s[i]-'0')%mod)*fastPow(10,i);tot%=mod;}return tot;}
string toString(int a){string s = "";while(a){s = (char)('0'+a%10) + s;a/=10;}return s;}

signed main(){
   	ios::sync_with_stdio(false);
	cin.tie(0);
		
	int t;
	cin >> t;
	
	while(t--){
		int n;
		cin >> n;
		
		vector< int > v(n*2);
		
		for(int i = 0; i < n*2; i++){
			cin >> v[i];
		}
		
		bool act = true;
		while(act){
			act = false;
			for(int i = 0; i < n*2; i++){
				if(v[(i+1)%(2*n)]==(v[i]+v[(i+2)%(2*n)])/2){
					swap(v[i],v[(i+1)%(2*n)]);
					act = true;
				}
			}
		}
		
		
		for(int a : v) cout << a << ' ';
		cout << endl;
	}
}
