https://www.acmicpc.net/problem/10994
def myStar(n ,idx):
length=4*n-3
if n==1:
mlist[idx][idx]='*'
return
for i in range(idx, length+idx):
mlist[idx][i]='*'
mlist[i][idx]='*'
mlist[idx+length-1][i]='*'
mlist[i][idx+length-1]='*'
return myStar(n-1, idx+2)
n=int(input())
lens=4*n-3
mlist=[[' ']*lens for _ in range(lens)]
myStar(n, 0)
for i in mlist:
print(''.join(i))
*************
* *
* ********* *
* * * *
* * ***** * *
* * * * * *
* * * * * * *
* * * * * *
* * ***** * *
* * * *
* ********* *
* *
*************