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

void findZigZagSequence(vector <long int > a,long int n){
    sort(a.begin(), a.end());
    long int mid = (n + 1)/2;
    long int st = mid - 1;
    long int ed = n - 1;
    while(st <= ed){
        swap(a[st], a[ed]);
        st = st + 1;
        ed = ed - 1;
    }
    for(long int i = 0; i < n; i++){
        if(i > 0) cout << " ";
        cout << a[i];
    }
    cout << endl;
}

int main()
{
    long int n, x;
    long int test_cases;
    cin >> test_cases;

    for(long int cs = 1; cs <= test_cases; cs++){
        cin >> n;
        vector <long int > a;
        for(long int i = 0; i < n; i++){
            cin >> x;
            a.push_back(x);
        }
        findZigZagSequence(a, n);
    }
    return 0;
}