SpriteKit Block positioning - sprite-kit

Question

I am trying to make a jump game in Xcode 5 with SpriteKit.
First I want to spawn Blocks in a random position, but reachable for the 'human' in the game that is jumping.
I got a 1. Block, that spawn at a set position. From this position, there should spawn a 2. Block, that can be + or - 80 higher or lower, and < 80 away. Now here is the problem, I don`t know how to code it in Xcode. My code so far :
SKTexture * BlockTexture1 = [SKTexture textureWithImageNamed:#"Block"];
BlockTexture1.filteringMode = SKTextureFilteringNearest;
SKTexture * BlockTexture2 = [SKTexture textureWithImageNamed:#"Block"];
BlockTexture2.filteringMode = SKTextureFilteringNearest;
SKSpriteNode * Block1 = [SKSpriteNode spriteNodeWithTexture:BlockTexture1];
[Block1 setScale:1];
Block1.position = CGPointMake( 100 , 150 );
Block1.physicsBody = [SKPhysicsBody bodyWithRectangleOfSize:Block1.size];
Block1.physicsBody.dynamic = NO;
Block1.physicsBody.usesPreciseCollisionDetection = YES;
Block1.zPosition = 3;
[self addChild:Block1];
SKSpriteNode * Block2 = [SKSpriteNode spriteNodeWithTexture:BlockTexture2];
[Block2 setScale:1];
Block2.position = CGPointMake( **Block1 + or - 80, Block 1 < 80** );
Block2.physicsBody = [SKPhysicsBody bodyWithRectangleOfSize:Block2.size];
Block2.physicsBody.dynamic = NO;
Block2.physicsBody.usesPreciseCollisionDetection = YES;
Block2.zPosition = 3;
[self addChild:Block2];

Answer 1

To get your started, something like this perhaps:
int block1x = 100;
int block1y = 150;
Block1.position = CGPointMake(block1x, block1y);
int block2x = 0;
int block2y = 0;
int r1 = arc4random() % 2; // produces random numbers between 0 and 1
if(r1 == 0)
block2x = block1x + 80;
if(r1 == 1)
block2x = block1x - 80;
int r2 = arc4random() % 2;
if(r2 == 0)
block2y = block1y + 80;
if(r2 == 1)
block2y = block1y - 80;
Block2.position = CGPointMake(block2x, block2y);