diff --git a/BlockTimestamp.sol b/BlockTimestamp.sol
new file mode 100644
index 0000000..43c14e6
--- /dev/null
+++ b/BlockTimestamp.sol
@@ -0,0 +1,26 @@
+// SPDX-License-Identifier: MIT
+pragma solidity ^0.6.10;
+
+/*
+Block timestamp manipulation
+
+Basic idea of the exploit
+- Miners can manipulate block.timestamp with some constraints
+
+Constraints
+- it must be after the previous block timestamp
+- it cannot be too far in the future
+*/
+
+contract Roulette {
+    constructor() public payable {}
+
+    function spin() external payable {
+        require(msg.value >= 1 ether); // must send 1 ether to play
+
+        if (block.timestamp % 7 == 0) {
+            (bool sent, ) = msg.sender.call{value: address(this).balance}("");
+            require(sent, "Failed to send Ether");
+        }
+    }
+}