diff --git a/2021/day-13/Cargo.toml b/2021/day-13/Cargo.toml
new file mode 100644
index 0000000..7f53c1c
--- /dev/null
+++ b/2021/day-13/Cargo.toml
@@ -0,0 +1,9 @@
+[package]
+authors = ["Joseph Chamochumbi <sephxd1234@gmail.com>"]
+edition = "2018"
+name = "day-13"
+version = "0.1.0"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+[dependencies]
+aoc = {git = "https://github.com/icyJoseph/advent-of-code.git"}
diff --git a/2021/day-13/src/main.rs b/2021/day-13/src/main.rs
new file mode 100644
index 0000000..762627c
--- /dev/null
+++ b/2021/day-13/src/main.rs
@@ -0,0 +1,103 @@
+use aoc;
+
+use std::collections::HashSet;
+
+#[derive(Hash, PartialEq, Eq)]
+struct Point {
+    x: usize,
+    y: usize,
+}
+
+impl Point {
+    fn fold(&mut self, dir: &str, at: usize) {
+        match dir {
+            "x" => {
+                self.x = if self.x > at { 2 * at - self.x } else { self.x };
+            }
+            "y" => {
+                self.y = if self.y > at { 2 * at - self.y } else { self.y };
+            }
+            _ => {}
+        }
+    }
+}
+
+fn solve(raw: String) -> () {
+    let spec = raw.trim().split("\n\n").collect::<Vec<&str>>();
+
+    let mut dots = spec[0]
+        .split("\n")
+        .map(|row| {
+            let coords = row
+                .split(",")
+                .map(|c| parse_num::<usize>(c))
+                .collect::<Vec<usize>>();
+
+            Point {
+                x: coords[0],
+                y: coords[1],
+            }
+        })
+        .collect::<Vec<Point>>();
+
+    let instructions = spec[1].split("\n");
+
+    let mut part_one = true;
+
+    for entry in instructions {
+        let spec = entry.replace("fold along ", "");
+        let inst = spec.split("=").collect::<Vec<&str>>();
+
+        let dir = inst[0];
+        let at = parse_num::<usize>(inst[1]);
+
+        dots.iter_mut().for_each(|p: &mut Point| p.fold(dir, at));
+
+        if part_one {
+            let mut visible: HashSet<&Point> = HashSet::new();
+
+            dots.iter().for_each(|p| {
+                visible.insert(p);
+            });
+
+            println!("Part Two: {}", visible.len());
+
+            part_one = false
+        }
+    }
+
+    let width = dots.iter().max_by(|p, q| p.x.cmp(&q.x)).unwrap().x;
+
+    let height = dots.iter().max_by(|p, q| p.y.cmp(&q.y)).unwrap().y;
+
+    let mut board = vec![vec![' '; width + 1]; height + 1];
+
+    dots.iter().for_each(|p| board[p.y][p.x] = '#');
+
+    println!("Part Two:");
+
+    for row in board {
+        println!("{}", string_vec(&row, ""));
+    }
+}
+
+fn main() {
+    let input = aoc::get_input(2021, 13);
+
+    solve(input);
+}
+
+// Utilities
+fn parse_num<T: std::str::FromStr>(str: &str) -> T {
+    match str.trim().parse::<T>() {
+        Ok(n) => n,
+        _ => panic!("Error parsing"),
+    }
+}
+
+fn string_vec<T: std::string::ToString>(vec: &Vec<T>, separator: &str) -> String {
+    vec.iter()
+        .map(|x| x.to_string())
+        .collect::<Vec<String>>()
+        .join(separator)
+}
diff --git a/2021/deno/day-13.ts b/2021/deno/day-13.ts
new file mode 100644
index 0000000..f7a50f1
--- /dev/null
+++ b/2021/deno/day-13.ts
@@ -0,0 +1,73 @@
+const input = await Deno.readTextFile("./input/day-13.in");
+// const input = await Deno.readTextFile("./input/example.in");
+
+const [dots, instructions] = input.split("\n\n");
+
+const coords = dots
+  .split("\n")
+  .map((row) => {
+    const [x, y] = row.split(",");
+    return { x: Number(x), y: Number(y) };
+  })
+  .flat(1);
+
+const foldV = (xf: number, grid: { x: number; y: number }[]) => {
+  return grid.map(({ x, y }) => ({
+    y,
+    x: x > xf ? 2 * xf - x : x
+  }));
+};
+
+const foldH = (yf: number, grid: { x: number; y: number }[]) => {
+  return grid.map(({ x, y }) => ({
+    x,
+    y: y > yf ? 2 * yf - y : y
+  }));
+};
+
+/**
+ * Part Two
+ */
+
+const print = (grid: { x: number; y: number }[]) => {
+  const width = 1 + Math.max(...grid.map(({ x }) => x));
+  const height = 1 + Math.max(...grid.map(({ y }) => y));
+
+  const board = Array.from({ length: height }, () =>
+    Array.from({ length: width }, () => " ")
+  );
+
+  grid.forEach(({ x, y }) => {
+    board[y][x] = "#";
+  });
+
+  for (const row of board) {
+    console.log(row.join(""));
+  }
+};
+
+let it = 0;
+let grid = coords.slice(0);
+
+for (const inst of instructions.split("\n")) {
+  const [dir, where] = inst.replace("fold along ", "").split("=");
+
+  const fn = dir === "x" ? foldV : foldH;
+
+  grid = fn(Number(where), grid);
+
+  if (it === 0) {
+    const visible: Set<string> = new Set();
+    grid.forEach(({ x, y }) => visible.add(`${x},${y}`));
+
+    /**
+     * Part One
+     */
+    console.log("Part One:", visible.size);
+  }
+
+  it += 1;
+}
+
+console.log("Part Two:");
+print(grid);