How to make this code more efficient ?

Question

Basically i've seen this code in the internet. It displays a lightning bolt pattern in asterisk and i want to make it more efficient by putting an input field that accepts integer only.

here's the code:
from math import ceil as c

lightning=lambda len : (" "*(len+1)+"*"*len+"\n"+"\n".join(" "*(len-i)+"*"+" "*(len-2)+"*" for i in range(len))+"\n*"+" "*(len-2)+"*"*(len*2-2)+"\n"+"\n".join("*"+" "*(len*3-5)+"*"for i in range(c(len/2)-(2 if len >4 else 1)))+"\n"+"*"*(len*2-3)+" "*(len-2)+"*"+"\n"+"\n".join(" "*(len*2-5-i)+"*"+" "*(len-2)+"*" for i in range(len-1))+"\n"+" "*(len-4)+"*"*len) if len > 3 else""

for i in range(2,5):
print(lightning(i))

Answer 1

This is quite good honestly but i was also scratching my head to do this the first time in a efficient way.