kal

def oneline(n: int, l=0):
    if (l==0):
       l!=2*n+1
    i=0
    if (l==2*n+1):
        while(i < n):
            print(i, sep='', end=' ', flush=True)
            i+=1
        while(i > -1):
            print(i, sep='', end=' ', flush=True)
            i-=1
        print("")
    else:
        rep=l-(2*n+1)
        while(i < n):
            print(i, sep='', end=' ', flush=True)
            i+=1
        for k in range(rep):
            print (i, sep='', end=' ', flush=True)
        while(i > -1):
            print(i, sep='', end=' ', flush=True)
            i-=1
        print("")

def triangle(n: int):
    i=0
    l=1
    while(i < n):
        oneline(i)
        i+=1
        l+=2
    while(i > -1):
        oneline(i, l)
        l+=2
        i-=1

triangle(4)