That is such a wonderful error coin to see. The double strike alignment is just awesome. An atypical example for sure.
Your 1918 over 1918 cent would have been one of my favorite Lincolns. Had I splurged the necessary bucks, the below coin would have been one of my favorite large cents -- a lovely 1823 over 1822 over 1823 over 1822.
That reminds me of when my son asked how he could double his money. I told him to give people a penny for their thoughts and they would give him their two cents.