Go: package main

import (
	"bufio"
	"os"
	"strconv"
	"fmt"
	"strings"
)

var scanner = bufio.NewScanner(os.Stdin)

func nextInt() int {
	scanner.Scan()
	i, e := strconv.Atoi(scanner.Text())
	if e != nil {
		panic(e)
	}
	return i
}

func main() {
	n := nextInt()
	for i := 0; i < n; i++ {
		scanner.Scan()
		points := strings.Split(scanner.Text(), " ")
		fpoints := make([]float64, 0)
		for _, v := range points {
			tmp, _ := strconv.ParseFloat(v, 64)
			fpoints = append(fpoints, tmp)
		}
		a := (fpoints[1]-fpoints[3])/(fpoints[0]-fpoints[2])
		b := (fpoints[5]-fpoints[7])/(fpoints[4]-fpoints[6])
		if a == b {
			fmt.Println("YES")
		} else {
			fmt.Println("NO")
		}
	}
}

C++: #include <bits/stdc++.h>

#define REP(i, a, b) for (int i = (int)(a); i < (int)(b); ++i)
#define rep(i, n) REP (i, 0, n)
#define mset(a, n) memset(a, n, sizeof(a))

using namespace std;

typedef long long ll;
typedef vector<int> vi;
typedef pair<int, int> pii;
typedef vector<pair<int, int> > vpii;

int main() {
	int n; cin >> n;
	while (n--) {
		double x1, y1, x2, y2, x3, y3, x4, y4;
		cin >> x1 >> y1 >> x2 >> y2 >> x3 >> y3 >> x4 >> y4;
		// 対角線の中点で判定
		// double cx1 = (x3 - x1) / 2.0;
		// double cy1 = (y3 - y1) / 2.0;
		// double cx2 = (x4 - x2) / 2.0;
		// double cy2 = (y4 - y2) / 2.0;
		// if (cx1 == cx2 && cy1 == cy2) {
		//  cout << "YES" << endl;
		// } else {
		//  cout << "NO" << endl;
		// }
		// 傾きで判定
		// if ((y2 - y1) / (x2 - x1) == (y4 - y3) / (x4 -x3)) {
		//  cout << "YES" << endl;
		// } else {
		//  cout << "NO" << endl;
		// }
		if ((y2 - y1) / (x2 - x1) == (y4 - y3) / (x4 - x3)) {
			cout << "YES" << endl;
		} else {
			cout << "NO" << endl;
		}
	}
}

C++: #include <stdio.h>

int main(void)
{
  int n,i;
  double x1,y1,x2,y2,x3,y3,x4,y4;
  int ans[100];
  
  scanf("%d", &n);
  for(i = 0;i < n;i++){
    scanf("%lf %lf %lf %lf %lf %lf %lf %lf", &x1, &y1, &x2, &y2, &x3, &y3, &x4, &y4);
  
    if( (y2-y1)/(x2-x1) == (y4-y3)/(x4-x3) ){
      ans[i] = 1;
    }else{
      ans[i] = 0;
    }
  }

  for(i = 0;i < n;i++){
    if(ans[i] == 1){
      printf("YES\n");
    }else{
      printf("NO\n");
    }
  }
  return 0;
}

C++: #include<bits/stdc++.h>
using namespace std;
 
signed main(){
int a;
cin>>a;
double c[8];
for(int b=0;b<a;b++){
    for(int d=0;d<8;d++)cin>>c[d];
    if(c[0]==c[2]&&c[4]==c[6])printf("YES\n");
    else if((c[1]-c[3])/(c[0]-c[2])==(c[5]-c[7])/(c[4]-c[6]))printf("YES\n");
    else printf("NO\n");
    }
}

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

int main() {
	int n; cin >> n;
	while (n--) {
		double x1, y1, x2, y2, x3, y3, x4, y4;
		cin >> x1 >> y1 >> x2 >> y2 >> x3 >> y3 >> x4 >> y4;
		// 対角線の中点で判定
		// double cx1 = (x3 - x1) / 2.0;
		// double cy1 = (y3 - y1) / 2.0;
		// double cx2 = (x4 - x2) / 2.0;
		// double cy2 = (y4 - y2) / 2.0;
		// if (cx1 == cx2 && cy1 == cy2) {
		//  cout << "YES" << endl;
		// } else {
		//  cout << "NO" << endl;
		// }
		// 傾きで判定
		if ((y2 - y1) / (x2 - x1) == (y4 - y3) / (x4 - x3)) {
			cout << "YES" << endl;
		} else {
			cout << "NO" << endl;
		}
	}
}

C++: // class point	の練習（クラスの高度な実装）
#include <iostream>
#include <iomanip>
#include <algorithm>
#include <cstdio>
#include <cstdlib>
#include <string>
#include <cmath>
#include <vector>
#include <queue>


typedef long long llong;
using namespace std;

#define SMALL_LIMIT 1e-12

int main() {
	int n;
	double x1, x2, x3, x4;
	double y1, y2, y3, y4;
	double xa, ya, xb, yb;

	cin >> n;
	for (int i = 0; i < n; i++) {
		cin >> x1 >> y1 >> x2 >> y2 >> x3 >> y3 >> x4 >> y4;
		xa = x2 - x1; ya = y2 - y1;
		xb = x4 - x3; yb = y4 - y3;
		if (abs(xa*yb - ya * xb) < SMALL_LIMIT)cout << "YES\n";
		else cout << "NO\n";
	}
	return 0;
}

C++: #include <iostream>

using namespace std;

typedef struct myvector{
  double x;
  double y;
}Vector;

Vector sub_vector(Vector& a, Vector& b)
{
  Vector ret;
  ret.x = b.x - a.x;
  ret.y = b.y - a.y;
  return ret;
}

double cross_product(Vector& a, Vector& b)
{
  return a.x * b.y - b.x * a.y;
}

int main()
{
  int n;
  Vector A, B, C, D;
  cin >> n;
  for(int i = 0; i < n; i++){
    cin >> A.x >> A.y >> B.x >> B.y >> C.x >> C.y >> D.x >> D.y;
    Vector AB = sub_vector(A, B);
    Vector CD = sub_vector(C, D);
    if(cross_product(AB, CD) == 0)
      cout << "YES" << endl;
    else 
      cout << "NO" << endl;
  }
}

C++: #include <bits/stdc++.h>
using namespace std;
int main(){
  int n;
  double x1,x2,x3,x4,y1,y2,y3,y4;
  cin >> n;
  string ans[n];
  for(int i=0;i<n;i++){
    cin >> x1 >> y1 >> x2 >> y2 >> x3 >> y3 >> x4 >> y4;
    if((y1-y2)/(x1-x2)==(y3-y4)/(x3-x4) and (y1-y3)/(x1-x3)!=(y1-y2)/(x1-x2) and x1-x2!=0 and x3-x4!=0 and y1-y2!=0 and y3-y4!=0){
      ans[i]="YES";
    }else{
      ans[i]="NO";
    }
  }
  for(int i=0;i<n;i++){
    cout << ans[i] << endl;
  }
  return 0;
}

C++: #include <iostream>
#include <algorithm>
#include <complex>

using namespace std;

typedef complex<double> P;
#define EPS (1e-10)
#define EQ(a,b) (abs((a)-(b)) < EPS)

// OÏ (cross product) : a~b = |a||b|sinÆ
double cross(P a, P b) {
  return (a.real() * b.imag() - a.imag() * b.real());
}
// 2¼üÌ½s»è : a//b <=> cross(a, b) = 0
int is_parallel(P a1, P a2, P b1, P b2) {
  return EQ( cross(a1-a2, b1-b2), 0.0 );
}
int main(){

	int n;
	cin>>n;
	for(int j = 0; j < n; j++){
		P v[4];
		for(int i = 0; i < 4; i++){
			double x,y;
			cin>>x>>y;
			v[i] = P(x,y);
		}
		if(is_parallel(v[0],v[1],v[2],v[3])){
			cout<<"YES"<<endl;
		}
		else
			cout<<"NO"<<endl;
	}

	return 0;
}

C++: #include <iostream>
using namespace std;
int main(){
  

  int dataSets;
  cin >> dataSets;
  for(int i=0;i<dataSets;i++){
    double x1, y1, x2, y2, x3, y3, x4, y4;
    cin >> x1 >> y1 >> x2 >> y2 >> x3 >> y3 >> x4 >> y4;
    if((y2-y1)*(x4-x3) - (x2-x1)*(y4-y3) == 0.0){
      cout << "YES" << endl;
    }else{
      cout << "NO" << endl;
    }
    
  }

  return 0;

}

C++: //include
//------------------------------------------
#include <vector>
#include <list>
#include <map>
#include <set>
#include <deque>
#include <stack>
#include <bitset>
#include <algorithm>
#include <functional>
#include <numeric>
#include <utility>
#include <sstream>
#include <iostream>
#include <iomanip>
#include <cstdio>
#include <cmath>
#include <cstdlib>
#include <cctype>
#include <string>
#include <cstring>
#include <ctime>
#include <climits>
#include <queue>

using namespace std;

//typedef
//------------------------------------------
typedef vector<int> VI;
typedef vector<VI> VVI;
typedef vector<string> VS;
typedef pair<int, int> PII;
typedef long long LL;

//container util
//------------------------------------------
#define ALL(a)  (a).begin(),(a).end()
#define RALL(a) (a).rbegin(), (a).rend()
#define PB push_back
#define MP make_pair
#define SZ(a) int((a).size())
#define EACH(i,c) for(typeof((c).begin()) i=(c).begin(); i!=(c).end(); ++i)
#define EXIST(s,e) ((s).find(e)!=(s).end())
#define SORT(c) sort((c).begin(),(c).end())

//repetition
//------------------------------------------
#define FOR(i,a,b) for(int i=(a);i<(b);++i)
#define REP(i,n)  FOR(i,0,n)

//constant
//--------------------------------------------
const double EPS = 1e-10;
const double PI  = acos(-1.0);

int main(){
  int N; cin >> N;
  for(;N--;){
	double x[4], y[4];
	REP(i,4)
	  cin >> x[i] >> y[i];
	//x[0] -= x[1], y[0] -= y[1], x[2] -= x[3], y[2] -= y[3];

	if(abs((x[0]-x[1])*(y[2]-y[3])-(x[2]-x[3])*(y[0]-y[1]))<EPS)
	  cout << "YES" << endl;
	else
	  cout << "NO" << endl;
  }
  
  return 0;
}