package BOJ;
import java.util.*;
public class Q10163 {
public static void main(String args[]){
int arr[][] = new int[1001][1001];
Scanner sc = new Scanner(System.in);
int T = sc.nextInt();
int str[] = new int[4];
int num[] = new int[T];
int cnt = 0;
for(int i = 0; i < T; i++){
for(int j = 0; j < 4; j++) {
str[j] = sc.nextInt();
}
for(int j = 1000-str[0]; j > 1000-str[2]; j--) {
for(int k = str[1]; k < str[1] + str[3]-1; k++) {
if(i > 0){
if(arr[j][k] == 1) cnt++;
}
arr[j][k] = 1;
}
}
num[i] = (str[2]*str[3]);
}
for(int i = 0; i < T; i++){
System.out.println(num[i] - cnt);
}
}
}