diff --git a/coin.py b/coin.py
new file mode 100644
index 0000000..2ee4fa6
--- /dev/null
+++ b/coin.py
@@ -0,0 +1,36 @@
+import numpy as np
+rng = np.random.default_rng()
+
+class Player:
+	def __init__(self) -> None:
+		pass
+	def play(self):
+		n = 1
+		while True:
+			if np.random.randint(2):
+				return n
+			else:
+				n += 1
+
+class Simulator:
+	def __init__(self, N:int) -> None:
+		self.player = Player()
+		self.N = N
+	def simulation(self) -> list:
+		total = 0
+		for _ in range(self.N):
+			total += self.player.play()
+		return total
+	def output(self, n:int) -> None:
+		results = np.array([self.simulation() for _ in range(n)])
+		wins = np.full(n, self.N)
+		wr = wins/results
+		print(f"finished {n} times of simulation!")
+		print("for total plays:\n\tmean\tstd")
+		print(f"\t{np.mean(results)}\t{np.std(results)}")
+		print("for win rates:\n\tmean\tstd")
+		print(f"\t{np.mean(wr)}\t{np.std(wr)}")
+
+sim = Simulator(1)
+sim.output(100000)
+print(np.log(2))