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

typedef long long int ll;
//#define max(a, b) (a < b ? b : a)
#define min(a, b) ((a > b) ? b : a)
#define TEXT freopen("azerah.in","r",stdin); freopen("azerah.out","w",stdout);
#define testcase int TT; cin >> TT; for (int tc = 1; tc <= TT; tc++)
#define POL(i,n) for (int i = 0 ; i < n ; ++i)
#define pb push_back
#define all(x) x.begin(),x.end()
#define pii pair<int,int>
#define F first
#define S second
//#define endl "\n"
typedef pair<int,int>PL;



void solve()
{
    int n,c=0;
    cin >> n;
    if(n==2)
    {
        cout << "1 0" << endl;
    }
    else if((n&(n-1))==0)cout << "impossible" << endl;
    else
    {
        vector<int>v;
        for(int i=0;i<n;i++)
        {
            if((c^i)==0)
            {
                if(i+1==n)
                {
                    v.pop_back();
                    v.pb(i);
                    v.pb(i-1);
                }
                else
                {
                    v.pb(i+1);
                    v.pb(i);
                }
                c^=i;
                c^=(i+1);
                i++;
            }
            else
            {
                v.pb(i);
                c^=i;
            }
        }
        POL(i,v.size())
        {
            cout << v[i] << " ";
        }
        cout << endl;
    }
}

int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);

    testcase
    {
        solve();
    }

    return 0;
}