def findZigZagSequence(a, n):
    a.sort()
    mid = int((n + 1)/2) - 1 # 1st Edit: added -1 for the correct mid
    a[mid], a[n-1] = a[n-1], a[mid]

    st = mid + 1
    ed = n - 2 # 2nd Edit: change -1 to -2 for the correct initial ed value
    while(st <= ed):
        a[st], a[ed] = a[ed], a[st]
        st = st + 1
        ed = ed - 1 #3rd Edit: changed +1 to -1 for the correct swap.

    for i in range (n):
        if i == n-1:
            print(a[i])
        else:
            print(a[i], end = ' ')
    return

test_cases = int(input())
for cs in range (test_cases):
    n = int(input())
    a = list(map(int, input().split()))
    findZigZagSequence(a, n)

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