diff --git a/assignment-1b/.gitignore b/assignment-1b/.gitignore
index 44d187f..699e25f 100644
--- a/assignment-1b/.gitignore
+++ b/assignment-1b/.gitignore
@@ -1,5 +1,6 @@
 /target
-/assignment-1
+/assignment-1b
+/raytracer1b
 /examples/*.png
 *.ppm
 *.zip
diff --git a/assignment-1b/Cargo.toml b/assignment-1b/Cargo.toml
index 63a1cf3..2d30ba5 100644
--- a/assignment-1b/Cargo.toml
+++ b/assignment-1b/Cargo.toml
@@ -4,6 +4,10 @@ authors = ["Michael Zhang <zhan4854@umn.edu>"]
 version = "0.1.0"
 edition = "2021"
 
+[[bin]]
+name = "raytracer1b"
+path = "src/main.rs"
+
 [dependencies]
 anyhow = "1.0.68"
 clap = { version = "4.1.4", features = ["derive"] }
diff --git a/assignment-1b/Makefile b/assignment-1b/Makefile
index d7d255e..de80502 100644
--- a/assignment-1b/Makefile
+++ b/assignment-1b/Makefile
@@ -8,7 +8,7 @@ PANDOC := pandoc
 CONVERT := convert
 
 HANDIN := hw1b.michael.zhang.zip
-BINARY := ./assignment-1b
+BINARY := ./raytracer1b
 WRITEUP := writeup.pdf
 SOURCES := $(shell find -name "*.rs")
 
@@ -27,7 +27,7 @@ $(BINARY): $(SOURCES)
 		-w /usr/src/myapp \
 		rust \
 		cargo build --release
-	mv target/release/assignment-1b $@
+	mv target/release/raytracer1b $@
 
 $(HANDIN): $(BINARY) $(WRITEUP) Makefile Cargo.toml Cargo.lock README.md $(EXAMPLES_PNG) $(EXAMPLES_PPM)
 	$(ZIP) -r $@ src examples $^
diff --git a/assignment-1b/assignment-1b b/assignment-1b/assignment-1b
deleted file mode 100755
index bc2f626..000000000
Binary files a/assignment-1b/assignment-1b and /dev/null differ
diff --git a/assignment-1b/examples/Hw1bSample1.txt b/assignment-1b/examples/Hw1bSample1.txt
new file mode 100755
index 000000000..dc42708
--- /dev/null
+++ b/assignment-1b/examples/Hw1bSample1.txt
@@ -0,0 +1,14 @@
+imsize 512 512
+eye 0 0 0
+viewdir 0 0.1 -1
+hfov 90
+updir 0 1 0
+bkgcolor 0.1 0.1 0.1
+light -1 -1 -1 0 0.9 0.5 0.05
+mtlcolor 0 1 0 1 1 1 0.6 0.2 0.2 10
+sphere 0 1.5 -4 1
+mtlcolor 0 1 0 1 1 1 0.1 0.8 0.2 10
+sphere -1.275 -0.75 -4 1
+mtlcolor 0 1 0 1 1 1 0.1 0.2 0.8 10
+sphere 1.275 -0.75 -4 1
+
diff --git a/assignment-1b/src/main.rs b/assignment-1b/src/main.rs
index 6235353..65c0cea 100644
--- a/assignment-1b/src/main.rs
+++ b/assignment-1b/src/main.rs
@@ -15,6 +15,7 @@ use std::path::PathBuf;
 use anyhow::Result;
 use clap::Parser;
 use rayon::prelude::{IntoParallelIterator, ParallelIterator};
+use scene::data::ObjectKind;
 
 use crate::image::Image;
 use crate::input_file::parse_input_file;
@@ -82,8 +83,12 @@ fn main() -> Result<()> {
   // Generate a parallel iterator for pixels
   // The iterator preserves order and uses row-major order
   let pixels_iter = (0..scene.image_height)
-    .into_par_iter()
-    .flat_map(|y| (0..scene.image_width).into_par_iter().map(move |x| (x, y)));
+    // .into_par_iter()
+    .flat_map(|y| {
+      (0..scene.image_width)
+        // .into_par_iter()
+        .map(move |x| (x, y))
+    });
 
   // Loop through every single pixel of the output file
   let pixels = pixels_iter
diff --git a/assignment-1b/src/scene/cylinder.rs b/assignment-1b/src/scene/cylinder.rs
index 07459ac..9a6ad16 100644
--- a/assignment-1b/src/scene/cylinder.rs
+++ b/assignment-1b/src/scene/cylinder.rs
@@ -132,8 +132,7 @@ impl ObjectKind for Cylinder {
       let c = rotated_cylinder_center;
 
       if r.z == 0.0 {
-        // No solutions here
-        vec![]
+        Vec::new() // No solutions here
       } else {
         vec![
           (-o.z + c.z + self.length / 2.0) / r.z,
@@ -177,3 +176,29 @@ impl ObjectKind for Cylinder {
     Ok(solutions.min_by_key(|ctx| ctx.time))
   }
 }
+
+#[cfg(test)]
+mod tests {
+  use nalgebra::Vector3;
+
+  use crate::{ray::Ray, scene::data::ObjectKind};
+
+  use super::Cylinder;
+
+  #[test]
+  fn test_cylinder() {
+    let cylinder = Cylinder {
+      center: Vector3::new(0.0, 0.0, 0.0),
+      direction: Vector3::new(0.0, 1.0, 0.0),
+      radius: 3.0,
+      length: 4.0,
+    };
+
+    let eye = Vector3::new(0.0, 3.0, 3.0);
+    let end = Vector3::new(0.0, 2.0, 2.0);
+    let ray = Ray::from_endpoints(eye, end);
+
+    let res = cylinder.intersects_ray_at(&ray);
+    panic!("Result: {res:?}");
+  }
+}
diff --git a/assignment-1b/src/scene/data.rs b/assignment-1b/src/scene/data.rs
index 8e67cf3..f053285 100644
--- a/assignment-1b/src/scene/data.rs
+++ b/assignment-1b/src/scene/data.rs
@@ -84,6 +84,7 @@ pub struct Scene {
   pub objects: Vec<Object>,
 }
 
+/// Information about an intersection
 #[derive(Derivative)]
 #[derivative(Debug, PartialEq, PartialOrd, Ord)]
 pub struct IntersectionContext {
diff --git a/assignment-1b/src/utils.rs b/assignment-1b/src/utils.rs
index 10b1680..1c798f7 100644
--- a/assignment-1b/src/utils.rs
+++ b/assignment-1b/src/utils.rs
@@ -25,7 +25,10 @@ where
 }
 
 /// Calculate the rotation matrix between the 2 given vectors
-/// Based on the method here: https://math.stackexchange.com/a/897677
+///
+/// Based on the method given [here][1].
+///
+/// [1]: https://math.stackexchange.com/a/897677
 pub fn compute_rotation_matrix(
   a: Vector3<f64>,
   b: Vector3<f64>,