diff --git a/Cargo.lock b/Cargo.lock
index 23f1596..1717794 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -26,6 +26,7 @@ dependencies = [
  "dhat",
  "itertools",
  "md5",
+ "periodic-table-on-an-enum",
  "pico-args",
  "regex",
  "tinyjson",
@@ -241,6 +242,12 @@ dependencies = [
  "wasm-bindgen",
 ]
 
+[[package]]
+name = "json"
+version = "0.12.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "078e285eafdfb6c4b434e0d31e8cfcb5115b651496faca5749b88fafd4f23bfd"
+
 [[package]]
 name = "lazy_static"
 version = "1.4.0"
@@ -265,9 +272,9 @@ dependencies = [
 
 [[package]]
 name = "log"
-version = "0.4.20"
+version = "0.4.22"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b5e6163cb8c49088c2c36f57875e58ccd8c87c7427f7fbd50ea6710b2f3f2e8f"
+checksum = "a7a70ba024b9dc04c27ea2f0c0548feb474ec5c54bba33a7f72f873a39d07b24"
 
 [[package]]
 name = "md5"
@@ -353,6 +360,15 @@ dependencies = [
  "windows-targets 0.48.5",
 ]
 
+[[package]]
+name = "periodic-table-on-an-enum"
+version = "0.3.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8ce462378b3f87d2ce8e615ad6596767655b10c7bb9e071a586ddd3f8c5c9351"
+dependencies = [
+ "json",
+]
+
 [[package]]
 name = "pico-args"
 version = "0.5.0"
diff --git a/Cargo.toml b/Cargo.toml
index a0ca638..38e134e 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -27,6 +27,7 @@ color-eyre = "0.6.3"
 dhat = { version = "0.3.3", optional = true }
 itertools = "0.13.0"
 md5 = "0.7.0"
+periodic-table-on-an-enum = "0.3.2"
 pico-args = "0.5.0"
 regex = "1.11.1"
 tinyjson = "2.5.1"
diff --git a/data/examples/11.txt b/data/examples/11.txt
new file mode 100644
index 0000000..0a01c5e
--- /dev/null
+++ b/data/examples/11.txt
@@ -0,0 +1,4 @@
+The first floor contains a hydrogen-compatible microchip and a lithium-compatible microchip.
+The second floor contains a hydrogen generator.
+The third floor contains a lithium generator.
+The fourth floor contains nothing relevant.
diff --git a/src/bin/11.rs b/src/bin/11.rs
new file mode 100644
index 0000000..2a52adb
--- /dev/null
+++ b/src/bin/11.rs
@@ -0,0 +1,307 @@
+advent_of_code::solution!(11);
+
+use periodic_table_on_an_enum::Element;
+use itertools::Itertools;
+
+#[derive(Debug, Clone, PartialEq, PartialOrd, Ord, Eq)]
+enum Item {
+    Generator(Element),
+    Chip(Element),
+}
+
+impl Item {
+    fn to_string(&self) -> String {
+        match self {
+            Item::Generator(e) => format!("[{:<2}G]", e.get_symbol()),
+            Item::Chip(e) => format!("[{:<2}C]", e.get_symbol()),
+        }
+    }
+}
+
+#[derive(Clone, PartialEq)]
+struct Floor {
+    items: Vec<Item>
+}
+
+impl std::fmt::Debug for Floor {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> Result<(), std::fmt::Error> {
+        write!(f, "F -> ")?;
+        for item in &self.items {
+            write!(f, "{:^7}", item.to_string())?;
+        }
+        Ok(())
+    }
+}
+
+#[derive(Clone, PartialEq)]
+struct State {
+    previous: Option<Box<State>>,
+    floors: [Floor; 4],
+    current_floor: usize,
+}
+
+fn is_hazardous(items: Vec<Item>) -> bool {
+    let mut chips: Vec<Element> = Vec::new();
+    let mut gens: Vec<Element> = Vec::new();
+    for item in items {
+        match item {
+            Item::Generator(el) => gens.push(el),
+            Item::Chip(el) => chips.push(el),
+        }
+    }
+
+    for chip in chips {
+        if !gens.contains(&chip) && gens.len() > 0 {
+            return true;
+        }
+    }
+    return false;
+}
+
+impl State {
+    fn init(floors: Vec<Floor>) -> Self {
+        if floors.len() != 4 {
+            panic!("Wrong number of floors !!");
+        }
+        Self {
+            previous: None,
+            current_floor: 0,
+            floors: floors.try_into().unwrap()
+        }
+    }
+
+    fn build_from(
+        other: &State,
+        prev_remaining: Vec<Item>,
+        current_floor: usize,
+        items: Vec<Item>,
+    ) -> State {
+        let mut floors: [Floor; 4] = other.floors.clone();
+        floors[other.current_floor].items = prev_remaining;
+        floors[current_floor].items = items;
+
+        let res = State {
+            previous: None,
+            current_floor: current_floor,
+            floors: floors,
+        };
+        res
+    }
+
+    fn next_states(&self) -> Vec<State> {
+        // from current floor:
+        // remove 1 or 2 elements of each
+        // put them above, or put them below (if possible)
+
+        let items = self.floors[self.current_floor].items.clone();
+        let mut subsets: Vec<Vec<Item>> = Vec::new();
+        for item in &items {
+            subsets.push(vec![item.clone()]);
+        }
+        for comb in items.iter().combinations(2) {
+            subsets.push(comb.into_iter().cloned().collect());
+        }
+
+        let above_items = if self.current_floor < 3 {
+            Some(self.floors[self.current_floor + 1].items.clone())
+        } else {
+            None
+        };
+        let below_items = if self.current_floor > 0 {
+            Some(self.floors[self.current_floor - 1].items.clone())
+        } else {
+            None
+        };
+
+        let res = subsets.into_iter().filter_map(
+            |set| {
+                let remaining: Vec<Item> = items
+                    .clone().into_iter()
+                    .filter(|f| !set.contains(f))
+                    .collect();
+                if is_hazardous(remaining.clone()) {
+                    None
+                } else {
+                    let mut res: Vec<State> = Vec::new();
+                    if let Some(mut its) = above_items.clone() {
+                        its.extend(set.clone());
+                        its.sort();
+                        if !is_hazardous(remaining.clone()) {
+                            // Build above State
+                            let mut new_state = State::build_from(
+                                &self,
+                                remaining.clone(),
+                                self.current_floor + 1,
+                                its
+                            );
+                            if self.previous != Some(Box::new(new_state.clone())) {
+                                let mut prev = self.clone();
+                                prev.previous = None;
+                                new_state.previous = Some(Box::new(prev));
+                                res.push(new_state);
+                            }
+                        }
+                    }
+                    if let Some(mut its) = below_items.clone() {
+                        its.extend(set.clone());
+                        its.sort();
+                        if !is_hazardous(remaining.clone()) {
+                            // Build below State
+                            let mut new_state = State::build_from(
+                                &self,
+                                remaining.clone(),
+                                self.current_floor - 1,
+                                its
+                            );
+                            if self.previous != Some(Box::new(new_state.clone())) {
+                                let mut prev = self.clone();
+                                prev.previous = None;
+                                new_state.previous = Some(Box::new(prev));
+                                res.push(new_state);
+                            }
+                        }
+                    }
+                    Some(res)
+                }
+            }
+        )
+        .flatten()
+        .collect::<Vec<State>>();
+        res
+    }
+
+    fn is_complete(&self) -> bool {
+        self.floors[0].items.is_empty() &&
+            self.floors[1].items.is_empty() &&
+            self.floors[2].items.is_empty()
+    }
+//     fn is_complete(self) -> bool;
+
+//     fn next_states(self) -> Vec<State>;
+}
+
+impl std::fmt::Debug for State {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> Result<(), std::fmt::Error> {
+        let mut floors = self.floors.clone().into_iter().enumerate().collect::<Vec<_>>();
+        floors.reverse();
+        for (n, floor) in floors {
+            let cur = if n == self.current_floor {'>'} else {' '};
+            writeln!(f, "{}{:?}{:?}", cur, n, floor)?;
+        }
+        Ok(())
+    }
+}
+
+fn parse_line(input: &str) -> Floor {
+    let mut words = input.split_whitespace();
+    let mut items: Vec<Item> = Vec::new();
+    loop {
+        words.by_ref().skip_while(|&w| w != "a").next();
+        if let Some(matter) = words.next() {
+            if let Some(it_type) = words.next() {
+                // let it_type = it_type.strip_suffix(".").unwrap_or(it_type);
+                let matter = matter
+                    .strip_suffix("-compatible")
+                    .unwrap_or(matter);
+                let matter = matter
+                    .strip_suffix(",")
+                    .unwrap_or(matter);
+                items.push(
+                    match it_type {
+                        g if g.starts_with("generator") =>
+                            Item::Generator(
+                                Element::from_name(matter.into())
+                                    .expect("Missing element?!")),
+                        c if c.starts_with("microchip") =>
+                            Item::Chip(
+                                Element::from_name(matter.into())
+                                    .expect("Missing element?!")),
+                        _ => {
+                            println!("{}", it_type);
+                            panic!("invalid item type detected?!");
+                        },
+                    }
+                );
+            } else {
+                println!("input: {:?}", input);
+                panic!("invalid input format?");
+            }
+        } else {
+            break;
+        }
+    }
+    items.sort();
+    Floor {
+        items
+    }
+}
+
+fn walk_through_states(iteration: usize, states: Vec<State>) -> (usize, State) {
+    // println!("Iteration {:?}", iteration);
+    // println!("States: {:?}", states);
+
+    if iteration > 10 {
+        return (42, states[0].clone());
+    }
+    
+    let states = states
+        .into_iter()
+        .flat_map(|s| s.next_states())
+        .collect::<Vec<State>>();
+    let complete: Vec<State> = states.clone().into_iter().filter_map(|s|
+        if s.is_complete() {
+            Some(s)
+        } else {
+            None
+        }
+    ).collect();
+    if !complete.is_empty() {
+        (iteration, complete[0].clone())
+    } else {
+        walk_through_states(iteration + 1, states)
+    }
+}
+
+pub fn part_one(input: &str) -> Option<usize> {
+    let floors: Vec<Floor> = input
+        .strip_suffix("\n")
+        .unwrap_or(input)
+        .lines()
+        .map(parse_line)
+        .collect();
+    let state = State::init(floors);
+
+    // let states = state.next_states();
+
+    // println!("Ok, trying a new one:");
+
+    // let next_states = states[0].next_states();
+
+    // None
+    
+    let (iterations, st) = walk_through_states(1, state.next_states());
+    println!("{:#?}", st);
+    println!("{:?}", iterations);
+    Some(iterations)
+}
+
+pub fn part_two(_input: &str) -> Option<u32> {
+    None
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_part_one() {
+        let result = part_one(&advent_of_code::template::read_file("examples", DAY));
+        assert_eq!(result, Some(42));
+    }
+
+    #[test]
+    fn test_part_two() {
+        let result = part_two(&advent_of_code::template::read_file("examples", DAY));
+        assert_eq!(result, None);
+    }
+}