diff --git a/unit08_blockchain/lab/src/ether02.sol b/unit08_blockchain/lab/src/ether02.sol
index 8b13789..e7b279a 100644
--- a/unit08_blockchain/lab/src/ether02.sol
+++ b/unit08_blockchain/lab/src/ether02.sol
@@ -1 +1,220 @@
+pragma solidity ^0.4.24;
 
+// ----------------------------------------------------------------------------
+// 'ENU Token' token contract
+//
+// Deployed to : 0xbB15B38e4ef6aF154b89A2E57E03Cd5cbD752233
+// Symbol      : ENUToken
+// Name        : ENU Token
+// Total supply: 100000000
+// Decimals    : 18
+
+// Based on https://github.com/bitfwdcommunity/Issue-your-own-ERC20-token/tree/master/contracts
+
+
+// ----------------------------------------------------------------------------
+// Safe maths
+// ----------------------------------------------------------------------------
+contract SafeMath {
+    function safeAdd(uint a, uint b) public pure returns (uint c) {
+        c = a + b;
+        require(c >= a);
+    }
+    function safeSub(uint a, uint b) public pure returns (uint c) {
+        require(b <= a);
+        c = a - b;
+    }
+    function safeMul(uint a, uint b) public pure returns (uint c) {
+        c = a * b;
+        require(a == 0 || c / a == b);
+    }
+    function safeDiv(uint a, uint b) public pure returns (uint c) {
+        require(b > 0);
+        c = a / b;
+    }
+}
+
+
+// ----------------------------------------------------------------------------
+// ERC Token Standard #20 Interface
+// https://github.com/ethereum/EIPs/blob/master/EIPS/eip-20-token-standard.md
+// ----------------------------------------------------------------------------
+contract ERC20Interface {
+    function totalSupply() public constant returns (uint);
+    function balanceOf(address tokenOwner) public constant returns (uint balance);
+    function allowance(address tokenOwner, address spender) public constant returns (uint remaining);
+    function transfer(address to, uint tokens) public returns (bool success);
+    function approve(address spender, uint tokens) public returns (bool success);
+    function transferFrom(address from, address to, uint tokens) public returns (bool success);
+
+    event Transfer(address indexed from, address indexed to, uint tokens);
+    event Approval(address indexed tokenOwner, address indexed spender, uint tokens);
+}
+
+
+// ----------------------------------------------------------------------------
+// Contract function to receive approval and execute function in one call
+//
+// Borrowed from MiniMeToken
+// ----------------------------------------------------------------------------
+contract ApproveAndCallFallBack {
+    function receiveApproval(address from, uint256 tokens, address token, bytes data) public;
+}
+
+
+// ----------------------------------------------------------------------------
+// Owned contract
+// ----------------------------------------------------------------------------
+contract Owned {
+    address public owner;
+    address public newOwner;
+
+    event OwnershipTransferred(address indexed _from, address indexed _to);
+
+    constructor() public {
+        owner = msg.sender;
+    }
+
+    modifier onlyOwner {
+        require(msg.sender == owner);
+        _;
+    }
+
+    function transferOwnership(address _newOwner) public onlyOwner {
+        newOwner = _newOwner;
+    }
+    function acceptOwnership() public {
+        require(msg.sender == newOwner);
+        emit OwnershipTransferred(owner, newOwner);
+        owner = newOwner;
+        newOwner = address(0);
+    }
+}
+
+
+// ----------------------------------------------------------------------------
+// ERC20 Token, with the addition of symbol, name and decimals and assisted
+// token transfers
+// ----------------------------------------------------------------------------
+contract BillToken is ERC20Interface, Owned, SafeMath {
+    string public symbol;
+    string public  name;
+    uint8 public decimals;
+    uint public _totalSupply;
+
+    mapping(address => uint) balances;
+    mapping(address => mapping(address => uint)) allowed;
+
+
+    // ------------------------------------------------------------------------
+    // Constructor
+    // ------------------------------------------------------------------------
+    constructor() public {
+        symbol = "ENUToken";
+        name = "ENU Token";
+        decimals = 18;
+        _totalSupply = 100000000000000000000000000;
+        balances[0xbB15B38e4ef6aF154b89A2E57E03Cd5cbD752233] = _totalSupply;
+        emit Transfer(address(0), 0xbB15B38e4ef6aF154b89A2E57E03Cd5cbD752233, _totalSupply);
+    }
+
+
+    // ------------------------------------------------------------------------
+    // Total supply
+    // ------------------------------------------------------------------------
+    function totalSupply() public constant returns (uint) {
+        return _totalSupply  - balances[address(0)];
+    }
+
+
+    // ------------------------------------------------------------------------
+    // Get the token balance for account tokenOwner
+    // ------------------------------------------------------------------------
+    function balanceOf(address tokenOwner) public constant returns (uint balance) {
+        return balances[tokenOwner];
+    }
+
+
+    // ------------------------------------------------------------------------
+    // Transfer the balance from token owner's account to to account
+    // - Owner's account must have sufficient balance to transfer
+    // - 0 value transfers are allowed
+    // ------------------------------------------------------------------------
+    function transfer(address to, uint tokens) public returns (bool success) {
+        balances[msg.sender] = safeSub(balances[msg.sender], tokens);
+        balances[to] = safeAdd(balances[to], tokens);
+        emit Transfer(msg.sender, to, tokens);
+        return true;
+    }
+
+
+    // ------------------------------------------------------------------------
+    // Token owner can approve for spender to transferFrom(...) tokens
+    // from the token owner's account
+    //
+    // https://github.com/ethereum/EIPs/blob/master/EIPS/eip-20-token-standard.md
+    // recommends that there are no checks for the approval double-spend attack
+    // as this should be implemented in user interfaces 
+    // ------------------------------------------------------------------------
+    function approve(address spender, uint tokens) public returns (bool success) {
+        allowed[msg.sender][spender] = tokens;
+        emit Approval(msg.sender, spender, tokens);
+        return true;
+    }
+
+
+    // ------------------------------------------------------------------------
+    // Transfer tokens from the from account to the to account
+    // 
+    // The calling account must already have sufficient tokens approve(...)-d
+    // for spending from the from account and
+    // - From account must have sufficient balance to transfer
+    // - Spender must have sufficient allowance to transfer
+    // - 0 value transfers are allowed
+    // ------------------------------------------------------------------------
+    function transferFrom(address from, address to, uint tokens) public returns (bool success) {
+        balances[from] = safeSub(balances[from], tokens);
+        allowed[from][msg.sender] = safeSub(allowed[from][msg.sender], tokens);
+        balances[to] = safeAdd(balances[to], tokens);
+        emit Transfer(from, to, tokens);
+        return true;
+    }
+
+
+    // ------------------------------------------------------------------------
+    // Returns the amount of tokens approved by the owner that can be
+    // transferred to the spender's account
+    // ------------------------------------------------------------------------
+    function allowance(address tokenOwner, address spender) public constant returns (uint remaining) {
+        return allowed[tokenOwner][spender];
+    }
+
+
+    // ------------------------------------------------------------------------
+    // Token owner can approve for spender to transferFrom(...) tokens
+    // from the token owner's account. The spender contract function
+    // receiveApproval(...) is then executed
+    // ------------------------------------------------------------------------
+    function approveAndCall(address spender, uint tokens, bytes data) public returns (bool success) {
+        allowed[msg.sender][spender] = tokens;
+        emit Approval(msg.sender, spender, tokens);
+        ApproveAndCallFallBack(spender).receiveApproval(msg.sender, tokens, this, data);
+        return true;
+    }
+
+
+    // ------------------------------------------------------------------------
+    // Don't accept ETH
+    // ------------------------------------------------------------------------
+    function () public payable {
+        revert();
+    }
+
+
+    // ------------------------------------------------------------------------
+    // Owner can transfer out any accidentally sent ERC20 tokens
+    // ------------------------------------------------------------------------
+    function transferAnyERC20Token(address tokenAddress, uint tokens) public onlyOwner returns (bool success) {
+        return ERC20Interface(tokenAddress).transfer(owner, tokens);
+    }
+}