Go: package main

import (
        "fmt"
        "math/big"
)

func main() {
        var x1, x2, x3, x4, y1, y2, y3, y4 big.Float
        var n int
        fmt.Scanf("%d", &n)
        for i := 0; i < n; i++ {
                fmt.Scanf("%f %f %f %f %f %f %f %f",
                        &x1, &y1, &x2, &y2, &x3, &y3, &x4, &y4)
                var lx, ly, mx, my, mul1, mul2, sub, zz big.Float
                lx.Sub(&x2, &x1)
                ly.Sub(&y2, &y1)
                mx.Sub(&x4, &x3)
                my.Sub(&y4, &y3)
                mul1.Mul(&lx, &my)
                mul2.Mul(&ly, &mx)
                sub.Sub(&mul1, &mul2)
                zz.SetFloat64(0.0)

                if sub.Cmp(&zz) == 0 {
                        fmt.Println("YES")
                } else {
                        fmt.Println("NO")
                }
        }
}

Python: import math
if __name__ == '__main__':
    n = int(input())
    for _ in range(n):
        x1,y1,x2,y2,x3,y3,x4,y4 = map(float,input().split())
        #print((y2-y1)/(x2-x1) - (y4-y3)/(x4-x3))
        '''if math.fabs(x1 - x2) <= 0.00001 and math.fabs( x3 - x4) <= 0.00001:
            print("YES")
        elif math.fabs(x1 - x2) <= 0.00001:
            print("NO")
        elif math.fabs(x3 - x4) <= 0.00001:
            print("NO")
        else:
        '''
        if math.fabs((x2-x1) * (y4-y3)-(x4-x3)*(y2-y1)) <= 0.00001:
            print("YES")
        else:
            print("NO")

Python: # Aizu Problem 0021: Parallelism
#
import sys, math, os

# read input:
PYDEV = os.environ.get('PYDEV')
if PYDEV=="True":
    sys.stdin = open("sample-input.txt", "rt")


N = int(input())
for n in range(N):
    x1, y1, x2, y2, x3, y3, x4, y4 = [float(_) for _ in input().split()]
    det = (x2 - x1) * (y4 - y3) - (y2 - y1) * (x4 - x3)
    print("YES" if det == 0 else "NO")

Python: N = (eval(input()))
for _ in range(N):
	x1, y1, x2, y2, x3, y3, x4, y4 = [eval(item) for item in input().split()]
	if (x1 == x2 and x3 == x4) or (y1 == y2 and y3 == y4):
		print('YES')
	elif (x1 - x2)/(y1 - y2) == (x3 - x4)/(y3 - y4):
		print('YES')
	else:
		print('NO')

Python: # AOJ 0021: Parallelism
# Python3 2018.6.15 bal4u

EPS = 1e-7

def EQ(a, b):
	return abs(a - b) < EPS
	
n = int(input())
for i in range(n):
	ax1, ay1, ax2, ay2, bx1, by1, bx2, by2 = list(map(float, input().split()))
	f = False
	if EQ(ax1, ax2) and EQ(bx1, bx2): f = True
	elif EQ((ay2-ay1)*(bx2-bx1), (ax2-ax1)*(by2-by1)): f = True
	print('YES' if f else 'NO')

Python: # ????????????????????°??????
import sys
from decimal import Decimal

def is_parallel(x1, y1, x2, y2, x3, y3, x4, y4):
    d1x = x2 - x1
    d1y = y2 - y1
    d2x = x4 - x3
    d2y = y4 - y3

    return d1x * d2y == d1y * d2x

def main():
    n = int(sys.stdin.readline().strip())

    for _ in range(n):
        data = sys.stdin.readline().strip().split(' ')
        x1 = Decimal(data[0])
        y1 = Decimal(data[1])
        x2 = Decimal(data[2])
        y2 = Decimal(data[3])
        x3 = Decimal(data[4])
        y3 = Decimal(data[5])
        x4 = Decimal(data[6])
        y4 = Decimal(data[7])

        if is_parallel(x1, y1, x2, y2, x3, y3, x4, y4):
            print('YES')
        else:
            print('NO')
            
if __name__ == '__main__':
    main()

Python: n = int(input())
for i in range(n):
    x1, y1, x2, y2, x3, y3, x4, y4 = map(float, input().split())    
    if abs( (x2 - x1) * (y4 - y3) - (y2 - y1) * (x4 - x3) ) < 1e-10:
        print('YES')
    else:
        print('NO')

Python: n = int(input())
for i in range(n):
    Date = list(map(float,input().split()))
    if Date[2] != Date[0] and Date[6] != Date[4]:
        if (Date[3] - Date[1]) * (Date[6] - Date[4]) == (Date[7] - Date[5]) * (Date[2] - Date[0]):
            print("YES")
            continue
        else:
            print("NO")
            continue
    elif Date[2] == Date[0] and Date[6] == Date[4]:
        print("YES")

Python: n = int(input())
for _ in range(n):
    x1, y1, x2, y2, x3, y3, x4, y4 = map(float, input().split())
    if abs((x2 - x1) * (y4 - y3) - (x4 - x3) * (y2 - y1)) < 1e-10:
        print("YES")
    else:
        print("NO")

Python: n = int(raw_input())
for i in range(n):
  p = map( float, raw_input().split() )
  flag = ( p[ 1 ] - p[ 0 ] ) * ( p[ 7 ] - p[ 6 ] ) == ( p[ 3 ] - p[ 2 ] ) * ( p[ 5 ] - p[ 4 ] )
  print ( flag and 'YES' ) or 'NO'

Python: # Aizu Problem 0021: Parallelism
#
import sys, math, os

# read input:
PYDEV = os.environ.get('PYDEV')
if PYDEV=="True":
    sys.stdin = open("sample-input.txt", "rt")


N = int(input())
for n in range(N):
    x1, y1, x2, y2, x3, y3, x4, y4 = [float(_) for _ in input().split()]
    det = (x2 - x1) * (y4 - y3) - (y2 - y1) * (x4 - x3)
    print("YES" if abs(det) < 1e-10  else "NO")

Python: 
n=int(input())

for i in range(n):
    xy=list(map(float,input().split(" ")))
    X1=xy[2]-xy[0]
    Y1=xy[3]-xy[1]
    X2=xy[6]-xy[4]
    Y2=xy[7]-xy[5]
    area=X1*X2-Y1*Y2
    if abs(area)<10e-12:
        print("YES")
    else:
        print("NO")

Python: # AOJ 0021: Parallelism
# Python3 2018.6.15 bal4u

EPS = 1e-7

def EQ(a, b):
	return True if abs(a - b) < EPS else False
	
n = int(input())
for i in range(n):
	ax1, ay1, ax2, ay2, bx1, by1, bx2, by2 = list(map(float, input().split()))
	print('YES' if EQ((ay2-ay1)*(bx2-bx1), (ax2-ax1)*(by2-by1)) else 'NO')

Python: r=[]
for i in range(int(input())):
    d=[float(i) for i in input().split()]
    if d[0]-d[2] != 0 and d[4]-d[6] != 0:
        a=(d[1]-d[3])/(d[0]-d[2])
        b=(d[5]-d[7])/(d[4]-d[6])
        if a==b:r.extend([1])
        else:r.extend([0])
    else:
        r.extend([0])
[print("YES") if i else print("NO") for i in r]

Python: import math
if __name__ == '__main__':
    n = int(input())
    for _ in range(n):
        x1,y1,x2,y2,x3,y3,x4,y4 = map(float,input().split())
        #print((y2-y1)/(x2-x1) - (y4-y3)/(x4-x3))
        '''if math.fabs(x1 - x2) <= 0.00001 and math.fabs( x3 - x4) <= 0.00001:
            print("YES")
        elif math.fabs(x1 - x2) <= 0.00001:
            print("NO")
        elif math.fabs(x3 - x4) <= 0.00001:
            print("NO")
        else:
        '''
        if math.fabs((y2-y1)/(x2-x1) - (y4-y3)/(x4-x3)) <= 0.00001:
            print("YES")
        else:
            print("NO")

Python: n = int(input())
for i in range(n):
    x1, y1, x2, y2, x3, y3, x4, y4 = map(float, input().split())
    x2 -= x1
    y2 -= y1
    x4 -= x3
    y4 -= y3
    if x2 == 0 or x4 == 0:
        if x2 == 0 and x4 == 0:
            print('YES')
        else:
            print('NO')
    else:
        if y2 / x2 == y4 / x4:
            print('YES')
        else:
            print('NO')

Python: for i in range(int(input())):
  a,b,c,d,e,f,g,h = map(float,input().split())
  if a == c:
    print("YES" if e == g else "NO")
  elif e == g:
    print("NO")
  else:
    print("YES" if (b-d)/(a-c) - (f-h)/(e-g) < 1e-10 else "NO")

Python: num=int(input())
for i in range (num):
    info=list(map(float,input().split()))
    if info[2]==info[0]:
        if info[6]==info[4]:
            print("YES")
        else:
            print("NO")

Python: for i in range(int(input())):
    x1,y1,x2,y2,x3,y3,x4,y4=map(lambda x: int(100000*float(x)),input().split())
    x12=x1-x2
    y12=y1-y2
    x34=x3-x4
    y34=y3-y4
    if x12*y34==y12*x34:
        print("YES")
    else:
        print("NO")

Python: # -*- coding:utf-8 -*-
def check_para(x1,y1,x2,y2,x3,y3,x4,y4):
    k1 = (y2-y1)/(x2-x1)
    k2 = (y4-y3)/(x4-x3)
    if abs(k1-k2) < 1e-10:
        print('YES')
    else:
        print('NO')

n = int(input())
for i in range(n):
    x1,y1,x2,y2,x3,y3,x4,y4 = map(float,input().split())
    check_para(x1,y1,x2,y2,x3,y3,x4,y4)

Python: n = int(input())
for line in range(n):
    x1, y1, x2, y2, x3, y3, x4, y4 = map(float, input().split())
    d = (x2 - x1)*(y4 - y3) - (y2 - y1)*(x4 - x3)
    if -10**-5 <d < 10**-5:
        print('YES')
    else:
        print('NO')