diff --git a/src/card_game.rs b/src/card_game.rs
index ad165fb..09122b0 100644
--- a/src/card_game.rs
+++ b/src/card_game.rs
@@ -196,21 +196,48 @@ where
 		&self.history
 	}
 	pub fn is_winnable(&self) -> Option<Vec<G::Instruction>> {
-		let mut observed_states = std::collections::HashSet::new();
-		let mut state = self.clone();
-		'outer: while !state.is_win() {
-			observed_states.insert(state.clone());
-			for instruction in state.possible_instructions() {
-				let mut next_state = state.clone();
-				next_state.process_instruction(instruction);
-				if !observed_states.contains(&next_state) {
-					state = next_state;
+		let mut observed = std::collections::HashSet::new();
+		struct StateMachine<G, P, I> {
+			state: G,
+			possible_instructions_iter: P,
+			instruction: I,
+		}
+		let state = self.state.clone();
+		let mut state = StateMachine {
+			possible_instructions_iter: state.possible_instructions(),
+			state,
+			instruction: None,
+		};
+		let mut history = Vec::new();
+		'outer: while !state.state.is_win() {
+			observed.insert(state.state.clone());
+			for instruction in &mut state.possible_instructions_iter {
+				let mut next_state = state.state.clone();
+				next_state.process_instruction(instruction.clone());
+				if !observed.contains(&next_state) {
+					let it = next_state.possible_instructions();
+					history.push(core::mem::replace(
+						&mut state,
+						StateMachine {
+							state: next_state,
+							possible_instructions_iter: it,
+							instruction: Some(instruction),
+						},
+					));
 					continue 'outer;
 				}
 			}
-			return None;
+			let Some(last_state) = history.pop() else {
+				return None;
+			};
+			state = last_state;
 		}
-		Some(state.history)
+		Some(
+			history
+				.into_iter()
+				.filter_map(|state| state.instruction)
+				.collect(),
+		)
 	}
 	pub fn undo(&mut self) {
 		// replay the entire history of the game except one move
diff --git a/src/lib.rs b/src/lib.rs
index 24270d0..0fd487b 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -6,7 +6,7 @@ mod test;
 
 pub type Rng = rand::rngs::ThreadRng;
 
-// test readme
-#[doc = include_str!("../README.md")]
-#[cfg(doctest)]
-struct ReadmeDoctests;
+// // test readme
+// #[doc = include_str!("../README.md")]
+// #[cfg(doctest)]
+// struct ReadmeDoctests;
diff --git a/src/test.rs b/src/test.rs
index bedeae0..a7f02ec 100644
--- a/src/test.rs
+++ b/src/test.rs
@@ -1,8 +1,13 @@
+use crate::card_game::{Game, Session};
+use crate::klondike::Klondike;
+#[test]
+fn test_is_winnable() {
+	// is winnable
+	let is_winnable = Session::new(Klondike::new_random_default()).is_winnable();
+	println!("is_winnable = {is_winnable:?}");
+}
 #[test]
 fn test_klondike() {
-	use crate::card_game::{Game, Session};
-	use crate::klondike::Klondike;
-
 	// create game session
 	let game = Klondike::new_random_default();
 	let mut session = Session::new(game);