diff --git a/Cargo.lock b/Cargo.lock
index 0256ee8..dc1a1e5 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -15,6 +15,7 @@ dependencies = [
 name = "aoc2024"
 version = "0.1.0"
 dependencies = [
+ "gcd",
  "itertools",
  "regex",
 ]
@@ -25,6 +26,12 @@ version = "1.15.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "48c757948c5ede0e46177b7add2e67155f70e33c07fea8284df6576da70b3719"
 
+[[package]]
+name = "gcd"
+version = "2.3.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1d758ba1b47b00caf47f24925c0074ecb20d6dfcffe7f6d53395c0465674841a"
+
 [[package]]
 name = "itertools"
 version = "0.14.0"
diff --git a/Cargo.toml b/Cargo.toml
index 9c89a58..6a6d476 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -4,5 +4,6 @@ version = "0.1.0"
 edition = "2024"
 
 [dependencies]
+gcd = "2.3.0"
 itertools = "0.14.0"
 regex = "1.12.2"
diff --git a/src/day8.rs b/src/day8.rs
index e0da849..e94220c 100644
--- a/src/day8.rs
+++ b/src/day8.rs
@@ -1,5 +1,10 @@
-use std::{collections::{HashMap, HashSet}, convert::Infallible, str::FromStr};
+use std::{
+    collections::{HashMap, HashSet},
+    convert::Infallible,
+    str::FromStr,
+};
 
+use gcd::Gcd;
 use itertools::Itertools;
 
 pub fn day8_part1(input: &str) -> String {
@@ -9,17 +14,43 @@ pub fn day8_part1(input: &str) -> String {
 }
 
 pub fn day8_part2(input: &str) -> String {
-    todo!()
+    let city: City = input.parse().unwrap();
+    let antinodes: HashSet<Point> = city.resonant_antinodes().collect();
+    antinodes.len().to_string()
 }
 
 fn antinodes(antenna1: Point, antenna2: Point) -> (Option<Point>, Option<Point>) {
     let distance: Vector2 = (antenna1, antenna2).into();
     let antinode1 = antenna2 + distance;
     let antinode2 = antenna1 - distance;
-    dbg!(antenna1, antenna2, distance, antinode1, antinode2);
     (antinode1, antinode2)
 }
 
+fn resonant_antinodes(antenna1: Point, antenna2: Point, width: usize, height: usize) -> Vec<Point> {
+    let distance: Vector2 = (antenna1, antenna2).into();
+    let distance = distance.simplified();
+    let mut last_antinode = antenna1;
+    let mut antinodes = vec![last_antinode];
+    while let Some(next_antinode) = last_antinode + distance {
+        if next_antinode.row >= height || next_antinode.col >= width {
+            break;
+        } else {
+            antinodes.push(next_antinode);
+            last_antinode = next_antinode;
+        }
+    }
+    let mut last_antinode = antenna1;
+    while let Some(next_antinode) = last_antinode - distance {
+        if next_antinode.row >= height || next_antinode.col >= width {
+            break;
+        } else {
+            antinodes.push(next_antinode);
+            last_antinode = next_antinode;
+        }
+    }
+    antinodes
+}
+
 #[derive(Clone, Copy, PartialEq, PartialOrd, Eq, Ord, Hash, Debug)]
 struct Point {
     row: usize,
@@ -74,6 +105,20 @@ impl From<(Point, Point)> for Vector2 {
     }
 }
 
+impl Vector2 {
+    fn simplified(&self) -> Self {
+        let mut retval = *self;
+        let pos_col_distance: usize = retval.col_distance.unsigned_abs();
+        let pos_row_distance: usize = retval.row_distance.unsigned_abs();
+        let gcd = pos_col_distance.gcd(pos_row_distance);
+        if gcd != 1 {
+            retval.col_distance /= gcd as isize;
+            retval.row_distance /= gcd as isize;
+        }
+        retval
+    }
+}
+
 #[derive(Debug)]
 struct City {
     width: usize,
@@ -116,12 +161,11 @@ impl City {
         retval.into_values().collect()
     }
     fn antenna_pairs(&self) -> impl Iterator<Item = (Point, Point)> {
-        let ap: Vec<(Point, Point)> = self.antenna_groups
+        self
+            .antenna_groups
             .iter()
             .flat_map(|group| group.iter().combinations(2))
-            .map(|combination| (*combination[0], *combination[1])).collect();
-        dbg!(&ap);
-        ap.into_iter()
+            .map(|combination| (*combination[0], *combination[1]))
     }
     fn antinodes(&self) -> impl Iterator<Item = Point> {
         self.antenna_pairs()
@@ -130,4 +174,9 @@ impl City {
             .flatten()
             .filter(|p| p.row < self.height && p.col < self.width)
     }
+    fn resonant_antinodes(&self) -> impl Iterator<Item = Point> {
+        self.antenna_pairs()
+            .flat_map(|(from, to)| resonant_antinodes(from, to, self.width, self.height))
+            .filter(|p| p.row < self.height && p.col < self.width)
+    }
 }
diff --git a/src/lib.rs b/src/lib.rs
index b1d16d2..9b174dc 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -361,6 +361,13 @@ mod tests {
         // assert!(result.parse::<u64>().unwrap() < 414); //too high
         assert_eq!(result, "369");
     }
+    #[test]
+    fn day8_part2_test() {
+        let test_result = day8::day8_part2(include_str!("../input/day8.test.txt"));
+        assert_eq!(test_result, "34");
+        let result = day8::day8_part2(include_str!("../input/day8.txt"));
+        assert_eq!(result, "1169");
+    }
 
     #[test]
     fn day7_part1_test() {