Update readme

2023/day4/README.md

@@ -54,3 +54,47 @@ the three matches after the first).
 So, in this example, the Elf's pile of scratchcards is worth `**13**` points.
 
 Take a seat in the large pile of colorful cards. **How many points are they worth in total?**
+
+# Part Two
+
+Just as you're about to report your findings to the Elf, one of you realizes that the rules have actually been printed 
+on the back of every card this whole time.
+
+There's no such thing as "points". Instead, scratchcards only cause you to win more scratchcards equal to the number 
+of winning numbers you have.
+
+Specifically, you win copies of the scratchcards below the winning card equal to the number of matches. So, if card 
+10 were to have 5 matching numbers, you would win one copy each of cards 11, 12, 13, 14, and 15.
+
+Copies of scratchcards are scored like normal scratchcards and have the same card number as the card they copied. So, 
+if you win a copy of card 10 and it has 5 matching numbers, it would then win a copy of the same cards that the 
+original card 10 won: cards 11, 12, 13, 14, and 15. This process repeats until none of the copies cause you to win 
+any more cards. (Cards will never make you copy a card past the end of the table.)
+
+This time, the above example goes differently:
+
+```
+Card 1: 41 48 83 86 17 | 83 86  6 31 17  9 48 53
+Card 2: 13 32 20 16 61 | 61 30 68 82 17 32 24 19
+Card 3:  1 21 53 59 44 | 69 82 63 72 16 21 14  1
+Card 4: 41 92 73 84 69 | 59 84 76 51 58  5 54 83
+Card 5: 87 83 26 28 32 | 88 30 70 12 93 22 82 36
+Card 6: 31 18 13 56 72 | 74 77 10 23 35 67 36 11
+```
+
+- Card 1 has four matching numbers, so you win one copy each of the next four cards: cards 2, 3, 4, and 5.
+- Your original card 2 has two matching numbers, so you win one copy each of cards 3 and 4.
+- Your copy of card 2 also wins one copy each of cards 3 and 4.
+- Your four instances of card 3 (one original and three copies) have two matching numbers, so you win four copies each of cards 4 and 5.
+- Your eight instances of card 4 (one original and seven copies) have one matching number, so you win eight copies of card 5.
+- Your fourteen instances of card 5 (one original and thirteen copies) have no matching numbers and win no more cards.
+- Your one instance of card 6 (one original) has no matching numbers and wins no more cards.
+
+Once all of the originals and copies have been processed, you end up with 1 instance of card 1, 2 instances of card 2, 
+4 instances of card 3, 8 instances of card 4, 14 instances of card 5, and 1 instance of card 6. In total, this example 
+pile of scratchcards causes you to ultimately have 30 scratchcards!
+
+Process all of the original and copied scratchcards until no more scratchcards are won. Including the original set of 
+scratchcards, how many total scratchcards do you end up with?
+
+