#include<iostream>
#include<algorithm>
#include<cstdio>
#include<vector>
#define ll long long
using namespace std;
ll gcd(ll a,ll b){
return b==0?a:gcd(b,a%b);
}
string str;
ll a[5000];
ll b[5000];
ll c[5000];
int main(){
int n,T;
cin>>T;
while(T--){
cin>>n;
vector<ll>arr(n);
vector<ll>f(n);
for(int i=0;i<n;i++)
{
cin>>arr[i];
}
sort(arr.begin(),arr.end());
int j=0;
int X=2;
for(int i=0,p=n-1;;)
{
if(X==1)
{
f[j]=arr[p];
p--;
X=2;
j++;
}
else
{
f[j]=arr[i];
i++;
X=1;
j++;
}
if(j==n)
break;
}
for(int i=n-1;i>=0;i--)
{
cout<<f[i]<<" ";
}
cout<<endl;
}
return 0;
}