Work on Day2 first star, few open issues

2025/Lessons.md

@@ -7,3 +7,11 @@ This is mostly so I can keep notes on my progress, in single markdown format so
 
 1. Read! Oh that brain of mine, skipping half the things and missing things like count clicks not end point dial
 2. Setup a proper test, make a smaller input test that you know the answer to to check the code
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+## Lessons second day
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+1. More git commits!
+2. Clear history so you don't accidentally cp day1 to day2 during testing. (Undo FTW)
+3. Put the central check (Serial Valid/Invalid) in a function so it's easy to add self checks in the beginning
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