/*
    Author: Zhikun Wang
*/
#include <bits/stdc++.h>
#define debug(x) cout<<#x<<'='<<x<<endl

using namespace std;
template<typename T> void read(T &x){
    x = 0;int f = 1;char ch = getchar();
    while(!isdigit(ch)){if(ch == '-')f*=-1;ch = getchar();}
    while(isdigit(ch)){x = x*10+ch-48; ch = getchar();}x*=f;
}
template<typename T, typename ... Args> void read(T &x,Args&... nxt){
    read(x);
    read(nxt...);
}

#define rep(i,a,b) for(int i=a;i<(b);++i)
#define all(x) begin(x),end(x)
#define sz(x) (int)(x).size()
typedef long long ll;
typedef pair<int,int> pii;
typedef vector<int> vi;

int T;
int main(){
    read(T);
    while(T--){
        ll a,b,c,d;
        read(a,b,c,d);
        ll ans = a;
        ans = min(ans,c-1);
        ans = min(ans,b-d);
        ans = min(ans,a-1);
        ans = min(ans,b-1);
        ans = min(ans,(a-1+abs(c-d))/2);
        if(c!=d){
            ans = min(ans,(a-1+abs(c-d)-1)/2);
        }
        cout<<ans*ans<<endl;
    }
    return 0;
}