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

def solve(values):
    dist1 = None
    dist2 = None
    values = list(values)
    for i in xrange(len(values)):
        for j in xrange(i+1,len(values)):
            d = (values[i][0]-values[j][0])**2 + (values[i][1]-values[j][1])**2
            if d != dist1 and d != dist2:
                if not dist1:
                    dist1 = d
                elif not dist2:
                    dist2 = d
                else:
                    return 'NO'
    return 'YES'
    
q = int(raw_input())
for _ in xrange(q):
    n = int(raw_input())
    values = set()
    for i in range(n):
        x,y = map(int,raw_input().split())
        values.add((x,y))
    if len(values) > 4:
        print 'NO'
    elif len(values) == 1:
        print 'YES'
    else:
        print solve(values)