def line(p1, p2):
    return p1[0], p2[0] - p1[0], p1[1], p2[1] - p1[1]

def intersect(l1, l2):
    a = l1[0]
    b = l1[1]
    c = l1[2]
    d = l1[3]
    e = l2[0]
    f = l2[1]
    g = l2[2]
    h = l2[3]
    if (b*h - d*f) != 0:
        t = (f*(c - g) - h*(a - e))/float(b*h - d*f)
        return [a + b*t, c + d*t]

def perp_line(p, l):
    a,b,c,d = l[0],l[1],l[2],l[3]

    if d != 0:
        m_p = -b/float(d)
        b_p = p[1] - m_p * p[0]
        return 0, 1,b_p, m_p
    else:
        return c,d, 0, 1
    
def distance(A, B):
    return ((A[0] - B[0])**2 + (A[1] - B[1])**2)

def is_between(A, B, C):
    return distance(A,C) + distance(B,C) == distance(A,B)

def get_corners(A,B,C):
    AB = line(A,B)
    CD = perp_line(C, AB)
    D = intersect(AB, CD)
    EFC = perp_line(C, CD)
    E = intersect(EFC, perp_line(A, EFC))
    F = intersect(EFC, perp_line(B, EFC))

    if is_between(E,C,F):
        F = C
        return A,D,C,E
    elif is_between(F,C,E):
        E = C
        return A,B,F,E
    else:
        return A,B,F,E

def lies_on_line(l, p):
    return p[1] == l[0]*p[0] + l[1]

def test(pl):
    if len(pl) <= 3:
        return True

    c1,c2,c3,c4 = get_corners(*pl[:3])
    
    l1 = line(c1,c2)
    l2 = line(c2,c3)
    l3 = line(c3,c4)
    l4 = line(c4,c1)

    for p in pl[3:]:
        if not (lies_on_line(l1,p) or lies_on_line(l2,p) or lies_on_line(l3,p) or lies_on_line(l4,p)):
            return False
    return True

q = int(raw_input())

for i in range(q):
    n = int(raw_input())
    pl = []
    for i in range(n):
        pl.append(map(float, raw_input().split(' ')))
    print ['NO', 'YES'][test(pl)]