# Enter your code here. Read input from STDIN. Print output to STDOUT
import math

def distance(p0, p1):
    return math.sqrt((p0[0] - p1[0])**2 + (p0[1] - p1[1])**2)

def isOnLine(a,b,c):
    return (distance(a,c) + distance(b,c)) == distance(a,b);

def isBetweenCorners(p,c0,c1,c2,c3):
    for corner1, corner2 in [(c0,c1),(c0,c2),(c1,c3),(c3,c2)]:
        if isOnLine(corner1, corner2, p):
            return True
    return False

def isRect(points, maxX, maxY, minX, minY):
    c0=(minX,minY); c1=(minX,maxY); c2=(maxX,minY); c3=(maxX,maxY)
    for p in points:
         if not isBetweenCorners(p,c0,c1,c2,c3):
                return 'NO'
    return 'YES'


q = int(raw_input())
for _q in range(q):
    n = int(raw_input())
    points = [(0,0) for x in range(n)]
    maxX = float('-inf'); maxY = float('-inf'); minX = float('inf'); minY = float('inf');
    for i in range(n):
        x,y = map(int,raw_input().split(' '))
        points[i] = (x,y)
        maxX = x if x > maxX else maxX
        maxY = y if y > maxY else maxY
        minX = x if x < minX else minX
        minY = y if y < minY else minY 
    print isRect(points, maxX, maxY, minX, minY)