Some funny things I noticed about Armor Penetration

So, weird thing about Flat Penetration vs Percentage Penetration, Flat Penetration is stronger against targets with less resistances whereas Percentage Penetration is stronger against targets with more resistances. I've graphed out an example from the damage multipliers of Youmuu's Ghostblade and the Last Whisper. In short, the purple line represents Youmuu's Ghostblade, Flat Penetration, while the blue line represents Last Whisper, Percentage based penetration. X is how much armor the target in question has whereas Y is the damage modifier.

I wanted to point this out to help the players - especially Top Laners - who don't know what to do in a losing lane when their opponent buys, for example, a . Many (Not all, but enough to make me worry) players seem to have built this misconception around Armor Penetration, specifically that any and all Armor Penetration straight up negates Armor. It's really not like that; damage from Flat Penetration falls off just as hard as not having Flat Penetration in the first place the more you build armor. In other words, for those of you faltering against enemies building a lot of Flat Penetration, don't panic. Just build the Armor or Magic Resist you think you would need otherwise; they're still just as helpful as ever against enemies who invest Flat Penetration. On a related note, for those players out there who want to snowball lanes through raw damage, and your opponent refuses to build any resistances towards your damage type, abuse this by buying Flat Penetration.

There was a second thing I noticed about Armor Penetration, but I realized that my commentary on it was more of a "Gameplay and Balance" sort of thing to talk about. If you want to see this through, please check out the other half of this thread.