Hello, I am following along with this tutorial, and I need some help understanding some code. In the interface of Terrain.h the following lines of code are there: Code: #define kMaxHillPoints 1000 int _offsetX; CGPoint _hillKeyPoints[kMaxHillKeyPoints]; CCSprite *_stripes; Why is there an underscore before offsetX and stripes, is that just a naming convention used by the author or is it a known Objective-C naming convention? I have the same question with the #define line, I have seen these before, but why is there a k in front of MaxHillPoints? Can someone also explain the CGPoint with the brackets beside it, what do the brackets mean? In the Terrain.m there is a synthesize line that looks like this: @synthesize stripes = _stripes; What this code mean? I have seen and used @synthesize, but why is the author setting it equal to something? I know this tutorial was written for IOS, but I am using the Mac port of Cocos2d. Thanks!