diff --git a/inputs/day13.txt b/inputs/day13.txt
new file mode 100644
index 0000000..3b6b5cc
--- /dev/null
+++ b/inputs/day13.txt
@@ -0,0 +1,15 @@
+#.##..##.
+..#.##.#.
+##......#
+##......#
+..#.##.#.
+..##..##.
+#.#.##.#.
+
+#...##..#
+#....#..#
+..##..###
+#####.##.
+#####.##.
+..##..###
+#....#..#
diff --git a/src/bin/day13.rs b/src/bin/day13.rs
new file mode 100644
index 0000000..abb14d1
--- /dev/null
+++ b/src/bin/day13.rs
@@ -0,0 +1,83 @@
+#![forbid(elided_lifetimes_in_paths, unsafe_code)]
+
+use aoc23::read;
+use chumsky::{prelude::*, text::int};
+use rayon::iter::{IntoParallelRefIterator as _, ParallelIterator as _};
+
+#[derive(Clone, Copy, Debug, Eq, PartialEq)]
+enum Cell {
+	Working,
+	Broken,
+	Unknown
+}
+
+impl Cell {
+	fn parser() -> impl Parser<char, Self, Error = Simple<char>> {
+		choice((
+			just('.').map(|_| Self::Working),
+			just('#').map(|_| Self::Broken),
+			just('?').map(|_| Self::Unknown)
+		))
+	}
+}
+
+struct Pattern {
+	grid: Vec<Vec<Cell>>
+}
+
+impl Pattern {
+	fn parser() -> impl Parser<char, Self, Error = Simple<char>> {
+		Cell::parser()
+			.repeated()
+			.at_least(1)
+			.then_ignore(just("\n"))
+			.repeated()
+			.at_least(1)
+			.map(|grid| Self { grid })
+	}
+}
+
+fn parser() -> impl Parser<char, Vec<Pattern>, Error = Simple<char>> {
+	Pattern::parser()
+		.separated_by(just("\n"))
+		.then_ignore(end())
+}
+
+fn main() -> anyhow::Result<()> {
+	let patterns = read("inputs/day13.txt", parser())?;
+
+	let mut rows = Vec::new();
+	let mut cols = Vec::new();
+	for Pattern { grid } in &patterns {
+		'i: for i in 1 .. grid.len() - 1 {
+			for j in 0 .. i.min(grid.len() - i) {
+				if grid[i - j - 1] != grid[i + j + 1] {
+					eprintln!("discarding cut {i} due to rows {}/{}", i - j - 1, i + j);
+					continue 'i;
+				}
+			}
+			rows.push(i);
+		}
+		println!("rows: {rows:?}");
+
+		'i: for i in 1 .. grid[0].len() - 1 {
+			for j in 0 .. i.min(grid[0].len() - i) {
+				for k in 0 .. grid.len() {
+					if grid[k][i - j - 1] != grid[k][i + j] {
+						eprintln!("discarding cut {i} due to cols {}/{}", i - j - 1, i + j);
+						continue 'i;
+					}
+				}
+			}
+			cols.push(i);
+		}
+		println!("cols: {cols:?}");
+	}
+
+	println!(
+		"{}",
+		rows.iter().sum::<usize>() + 100 * cols.iter().sum::<usize>()
+	);
+
+	Ok(())
+}