diff --git a/example/create_basic_chain.php b/example/create_basic_chain.php
index 99a3cf5..72977ed 100644
--- a/example/create_basic_chain.php
+++ b/example/create_basic_chain.php
@@ -1,8 +1,9 @@
 <?php
-require(__DIR__.'/../vendor/autoload.php');
 
-use OhMyBrew\Blockchain\Blockchain;
+require __DIR__.'/../vendor/autoload.php';
+
 use OhMyBrew\Blockchain\Block;
+use OhMyBrew\Blockchain\Blockchain;
 
 // Get the number of runs
 if (!isset($argv[1])) {
@@ -11,10 +12,10 @@
 $runs = intval($argv[1]);
 
 // Color setup
-$RED="\033[0;31m";
-$BLUE="\033[0;34m";
-$YELLOW="\033[1;33m";
-$NC="\033[0m";
+$RED = "\033[0;31m";
+$BLUE = "\033[0;34m";
+$YELLOW = "\033[1;33m";
+$NC = "\033[0m";
 
 // Create chain
 $bc = new Blockchain();
@@ -24,7 +25,7 @@
 for ($i = 0; $i < $runs; $i++) {
     // Build block
     $block = $bc->buildBlock(5, "Hello World {$i}");
-    echo $RED.">>> ".($i === 0 ? "GENESIS block" : "Block #{$i}") . " built{$NC}\n";
+    echo $RED.'>>> '.($i === 0 ? 'GENESIS block' : "Block #{$i}")." built{$NC}\n";
 
     // Mine it and create a hash
     echo "{$BLUE}Mining...{$NC}\n";
@@ -40,7 +41,7 @@
 
 // Done, output results
 $bcHash = hash('sha256', json_encode($bc->getChain()));
-echo "Blockchain hash is ".$bcHash." with ".intval($argv[1])." valid blocks added to the chain.\n";
+echo 'Blockchain hash is '.$bcHash.' with '.intval($argv[1])." valid blocks added to the chain.\n";
 
 // Write chain to file
 file_put_contents(__DIR__."/{$bcHash}.json", json_encode($bc->getChain(), JSON_PRETTY_PRINT));
diff --git a/example/load_chain.php b/example/load_chain.php
index 4cbff96..1be0b81 100644
--- a/example/load_chain.php
+++ b/example/load_chain.php
@@ -1,14 +1,15 @@
 <?php
-require(__DIR__.'/../vendor/autoload.php');
 
-use OhMyBrew\Blockchain\Blockchain;
+require __DIR__.'/../vendor/autoload.php';
+
 use OhMyBrew\Blockchain\Block;
+use OhMyBrew\Blockchain\Blockchain;
 
 // Color setup
-$RED="\033[0;31m";
-$BLUE="\033[0;34m";
-$YELLOW="\033[1;33m";
-$NC="\033[0m";
+$RED = "\033[0;31m";
+$BLUE = "\033[0;34m";
+$YELLOW = "\033[1;33m";
+$NC = "\033[0m";
 
 // Locate the blockchain data and decode it
 if (!isset($argv[1])) {
@@ -24,7 +25,7 @@
     $chain[] = new Block(array_merge(
         $blockData,
         [
-            'previous' => isset($chain[$key - 1]) ? $chain[$key - 1] : null
+            'previous' => isset($chain[$key - 1]) ? $chain[$key - 1] : null,
         ]
     ));
 }
@@ -36,7 +37,7 @@
 // Verify the chain
 if ($bc->isValidChain()) {
     echo "Chain is: {$BLUE}Valid{$NC}\n";
-    echo "Blockchain hash is ".hash('sha256', json_encode($chain)) . " which matches the file input\n";
+    echo 'Blockchain hash is '.hash('sha256', json_encode($chain))." which matches the file input\n";
 } else {
     echo "Chain is: {$RED}Invalid{$NC}\n";
 }
diff --git a/src/OhMyBrew/Blockchain/Block.php b/src/OhMyBrew/Blockchain/Block.php
index a8de908..54151ed 100644
--- a/src/OhMyBrew/Blockchain/Block.php
+++ b/src/OhMyBrew/Blockchain/Block.php
@@ -2,9 +2,9 @@
 
 namespace OhMybrew\Blockchain;
 
-use \JsonSerializable;
-use Symfony\Component\OptionsResolver\OptionsResolver;
+use JsonSerializable;
 use Symfony\Component\OptionsResolver\Options;
+use Symfony\Component\OptionsResolver\OptionsResolver;
 
 class Block implements JsonSerializable
 {
@@ -19,7 +19,7 @@ class Block implements JsonSerializable
      *
      * @return Block
      */
-    public function __construct(?array $state, ?Block $previous = null)
+    public function __construct(?array $state, ?self $previous = null)
     {
         if (!isset(self::$resolver)) {
             self::$resolver = new OptionsResolver();
@@ -38,7 +38,7 @@ public function __construct(?array $state, ?Block $previous = null)
     /**
      * Get the block index.
      *
-     * @return integer
+     * @return int
      */
     public function getIndex() : int
     {
@@ -48,7 +48,7 @@ public function getIndex() : int
     /**
      * Get the nonce result from mining.
      *
-     * @return null|integer
+     * @return null|int
      */
     public function getNonce() : ?int
     {
@@ -58,7 +58,7 @@ public function getNonce() : ?int
     /**
      * Get the difficulty for the mining.
      *
-     * @return integer
+     * @return int
      */
     public function getDifficulty() : int
     {
@@ -68,7 +68,7 @@ public function getDifficulty() : int
     /**
      * Get the timestamp of the block creation.
      *
-     * @return integer
+     * @return int
      */
     public function getTimestamp() : int
     {
@@ -106,11 +106,11 @@ public function getPreviousHash() : ?string
     }
 
     /**
-     * Get the previous block, if available
+     * Get the previous block, if available.
      *
      * @return null|Block
      */
-    public function getPrevious() : ?Block
+    public function getPrevious() : ?self
     {
         return $this->state['previous'];
     }
@@ -147,7 +147,7 @@ public function generateHash(?bool $assign = false) : string
      *
      * @return Block
      */
-    public function mine() : Block
+    public function mine() : self
     {
         $nonce = 0;
         while (!$this->validateNonce($nonce)) {
@@ -161,7 +161,7 @@ public function mine() : Block
     /**
      * Validates an nonce.
      *
-     * @param null|integer $nonce The new nonce value to test
+     * @param null|int $nonce The new nonce value to test
      *
      * @return bool
      */
@@ -203,13 +203,13 @@ public function jsonSerialize() : array
     protected function jsonSerializeData() : array
     {
         return [
-            'index' => $this->getIndex(),
-            'nonce' => $this->getNonce(),
-            'difficulty' => $this->getDifficulty(),
-            'timestamp' => $this->getTimestamp(),
-            'data' => $this->getData(),
+            'index'         => $this->getIndex(),
+            'nonce'         => $this->getNonce(),
+            'difficulty'    => $this->getDifficulty(),
+            'timestamp'     => $this->getTimestamp(),
+            'data'          => $this->getData(),
             'previous_hash' => $this->getPreviousHash(),
-            'hash' => $this->getHash()
+            'hash'          => $this->getHash(),
         ];
     }
 
@@ -230,6 +230,7 @@ protected function hashAlgo() : string
      * Typing out and remembering a list of arguments for the constructor.
      *
      * @param OptionsResolver $resolver
+     *
      * @return void
      */
     public function configureOptions(OptionsResolver $resolver) : void
@@ -241,7 +242,7 @@ public function configureOptions(OptionsResolver $resolver) : void
         );
         $resolver->setAllowedTypes(
             'previous',
-            ['null', Block::class]
+            ['null', self::class]
         );
 
         $resolver->setDefault(
diff --git a/src/OhMyBrew/Blockchain/Blockchain.php b/src/OhMyBrew/Blockchain/Blockchain.php
index f1a51b4..f95e772 100644
--- a/src/OhMyBrew/Blockchain/Blockchain.php
+++ b/src/OhMyBrew/Blockchain/Blockchain.php
@@ -2,10 +2,9 @@
 
 namespace OhMyBrew\Blockchain;
 
-use \Exception;
-use \IteratorAggregate;
-use \ArrayIterator;
-use OhMyBrew\Blockchain\Block;
+use ArrayIterator;
+use Exception;
+use IteratorAggregate;
 
 class Blockchain implements IteratorAggregate
 {
@@ -53,6 +52,7 @@ public function getIterator() : ArrayIterator
     public function getPreviousBlock(?int $index = null) : ?Block
     {
         $target = is_null($index) ? count($this->getChain()) - 1 : $index - 1;
+
         return $target >= 0 ? $this->getChain()[$target] : null;
     }
 
@@ -128,7 +128,7 @@ public function isValid() : bool
      *
      * @return Blockchain|Exception
      */
-    public function addBlock(Block $block, ?bool $validateChain = false) : ?Blockchain
+    public function addBlock(Block $block, ?bool $validateChain = false) : ?self
     {
         if (!$this->isValidBlock($block)) {
             throw new Exception('Block not valid, cannot add block to chain');
@@ -139,6 +139,7 @@ public function addBlock(Block $block, ?bool $validateChain = false) : ?Blockcha
         }
 
         $this->chain[] = $block;
+
         return $this;
     }
 
@@ -155,8 +156,8 @@ public function buildBlock(int $difficulty, string $data, ?string $blockClass =
     {
         return new $blockClass([
             'difficulty' => $difficulty,
-            'previous' => $this->getPreviousBlock(),
-            'data' => $data
+            'previous'   => $this->getPreviousBlock(),
+            'data'       => $data,
         ]);
     }
 }
diff --git a/tests/BlockTest.php b/tests/BlockTest.php
index f13d3dc..1377e74 100644
--- a/tests/BlockTest.php
+++ b/tests/BlockTest.php
@@ -24,7 +24,7 @@ public function shouldRequireArrayOnConstruct()
      * @test
      * @expectedException Symfony\Component\OptionsResolver\Exception\MissingOptionsException
      * @expectedExcepionMessage The required option "difficulty" is missing.
-     * 
+     *
      * Should require difficulty set for mining.
      */
     public function shouldRequireDifficulty()
@@ -139,8 +139,8 @@ public function shouldMineBlock()
     {
         $block = new Block([
             'difficulty' => 1,
-            'data' => 'Hello World',
-            'timestamp' => 1519403271 // So we can keep the mining result constant for this data/block
+            'data'       => 'Hello World',
+            'timestamp'  => 1519403271, // So we can keep the mining result constant for this data/block
         ]);
 
         $this->assertFalse($block->isMined());
diff --git a/tests/BlockchainTest.php b/tests/BlockchainTest.php
index 578239c..b6f6bc3 100644
--- a/tests/BlockchainTest.php
+++ b/tests/BlockchainTest.php
@@ -2,7 +2,7 @@
 
 namespace OhMyBrew\Blockchain;
 
-use \ReflectionClass;
+use ReflectionClass;
 
 class BlockchainTest extends \PHPUnit\Framework\TestCase
 {
@@ -64,7 +64,7 @@ public function shouldCreateBlock()
      * @test
      * @expectedException \Exception
      * @exceptedExceptionMessage Block not valid, cannot add block to chain
-     * 
+     *
      * Should not add block to chain who hasnt been mined or invalid.
      */
     public function shouldNotAddInvalidBlockToChain()
@@ -76,7 +76,7 @@ public function shouldNotAddInvalidBlockToChain()
 
     /**
      * @test
-     * 
+     *
      * Should add block if valid block.
      */
     public function shouldAddValidBlockToChain()
@@ -96,7 +96,7 @@ public function shouldAddValidBlockToChain()
 
     /**
      * @test
-     * 
+     *
      * Should validate chain.
      */
     public function shouldValidateChain()
@@ -117,7 +117,7 @@ public function shouldValidateChain()
      * @test
      * @expectedException \Exception
      * @expectedExceptionMessage Blockchain is invalid, cannot add block to chain
-     * 
+     *
      * Should invalidate chain (tampering maybe?)
      */
     public function shouldInvalidateChain()
@@ -165,7 +165,7 @@ public function shouldInvalidateChain()
 
     /**
      * @test
-     * 
+     *
      * Should confirm blocks are the same.
      */
     public function shouldConfirmBlocksAreTheSame()
@@ -183,7 +183,7 @@ public function shouldConfirmBlocksAreTheSame()
 
     /**
      * @test
-     * 
+     *
      * Input of chain should match output
      */
     public function shouldMatchInputAndOutput()
@@ -193,7 +193,7 @@ public function shouldMatchInputAndOutput()
             $chain[] = new Block(array_merge(
                 $blockData,
                 [
-                    'previous' => isset($chain[$key - 1]) ? $chain[$key - 1] : null
+                    'previous' => isset($chain[$key - 1]) ? $chain[$key - 1] : null,
                 ]
             ));
         }