Next, we will turn our attention to the creation of the game walls. There are two types of walls we need to address: walls created by a player's bike and the border walls around the playing grid. We will start by looking at how we can build our boundary walls.
Before we look at the code, it is important to know two items that are set up in our init method of the
CLPlayfieldLayer class. First, our CCSpriteBatchNode is in the variable cyclesheet. The second is that we have created an NSMutableArray called bikeWalls that will hold the CCSprite objects for all created walls (we will see this later, when we look at the init method in the CLPlayfieldLayer class). This array will be used in our collision detection, so we need to have our outer walls included in it.
-(void) createWallFrom:(CGPoint)orig to:(CGPoint)dest {
CCSprite *aWall = [CCSprite
spriteWithSpriteFrameName:IMG_SPECK];
[aWall setColor:ccYELLOW...