import sys
input = lambda :sys.stdin.readline()[:-1]
ni = lambda :int(input())
na = lambda :list(map(int,input().split()))
yes = lambda :print("yes");Yes = lambda :print("Yes")
no = lambda :print("no");No = lambda :print("No")
#######################################################################
b = 500
def dist(a, b):
    return abs(a[0] - b[0]) + abs(a[1] - b[1])

for _ in range(ni()):
    n, l = na()
    l += 1
    p = []
    for i in range(n):
        x, y = na()
        p.append([x*b//l,[y if (x*b//l)%2 else -y] , x, y])
    p = sorted(p)
    print(n)
    s = 0
    for i in range(n):
        s += dist(p[i][2:], p[(i+1)%n][2:])
        print(*p[i][2:])
    assert s <= 1000*(l-1)