diff --git a/output.ppm b/output.ppm
deleted file mode 100644
index 1d7b780..0000000
Binary files a/output.ppm and /dev/null differ
diff --git a/src/tests/cg_example.cu b/src/tests/cg_example.cu
new file mode 100644
index 0000000..fafaec8
--- /dev/null
+++ b/src/tests/cg_example.cu
@@ -0,0 +1,102 @@
+#include <cuda_runtime.h>
+#include <device_launch_parameters.h>
+#include <iostream>
+#include <cmath>
+
+#include "linalg/linalg.h"
+#include "objs/sphere.h"
+#include "img/handler.h"
+
+#define WIDTH 3840
+#define HEIGHT 2160
+#define SAMPLES_PER_PIXEL 8
+
+
+__device__ Vec3 phongShading(const Vec3& point, const Vec3& normal, const Vec3& lightDir, const Vec3& viewDir, const Vec3& color) {
+    double ambientStrength = 0.1;
+    double diffuseStrength = 0.8;
+    double specularStrength = 0.5;
+    int shininess = 64;
+
+    Vec3 ambient = color * ambientStrength;
+    double diff = max(normal.dot(lightDir), 0.0);
+    Vec3 diffuse = color * (diffuseStrength * diff);
+
+    Vec3 reflectDir = (normal * (2.0 * normal.dot(lightDir)) - lightDir).normalize();
+    double spec = pow(max(viewDir.dot(reflectDir), 0.0), shininess);
+    Vec3 specular = Vec3(1.0, 1.0, 1.0) * (specularStrength * spec);
+
+    return ambient + diffuse + specular;
+}
+
+__global__ void renderKernel(unsigned char* framebuffer, Sphere* spheres, int numSpheres, Vec3 lightPos) {
+    int x = blockIdx.x * blockDim.x + threadIdx.x;
+    int y = blockIdx.y * blockDim.y + threadIdx.y;
+    if (x >= WIDTH || y >= HEIGHT) return;
+
+    int pixelIndex = (y * WIDTH + x) * 3;
+    Vec3 rayOrigin(0, 0, 0);
+    Vec3 colCum(0, 0, 0);
+
+    double spp = static_cast<double>(SAMPLES_PER_PIXEL);
+    for (int sample = 0; sample < SAMPLES_PER_PIXEL; sample++) {
+        double u = (x + (sample / spp) - WIDTH / 2.0) / WIDTH;
+        double v = (y + (sample / spp) - HEIGHT / 2.0) / HEIGHT;
+        Vec3 rayDir(u, v, 1.0);
+        rayDir = rayDir.normalize();
+
+        for (int i = 0; i < numSpheres; ++i) {
+            double t;
+            if (spheres[i].intersect(rayOrigin, rayDir, t)) {
+                Vec3 hitPoint = rayOrigin + rayDir * t;
+                Vec3 normal = (hitPoint - spheres[i].center).normalize();
+                Vec3 lightDir = (lightPos - hitPoint).normalize();
+                Vec3 viewDir = -rayDir;
+
+                colCum = colCum + phongShading(hitPoint, normal, lightDir, viewDir, spheres[i].color);
+            }
+        }
+    }
+
+    // Average color across all samples
+    Vec3 color = colCum * (1.0 / SAMPLES_PER_PIXEL);
+
+    framebuffer[pixelIndex] = static_cast<unsigned char>(fmin(color.x, 1.0) * 255);
+    framebuffer[pixelIndex + 1] = static_cast<unsigned char>(fmin(color.y, 1.0) * 255);
+    framebuffer[pixelIndex + 2] = static_cast<unsigned char>(fmin(color.z, 1.0) * 255);
+}
+
+
+
+int main() {
+    Sphere spheres[] = {
+        { Vec3(0, 0, 5), 1.0, Vec3(1.0, 0.0, 0.0) },  // Red sphere
+        { Vec3(-2, 1, 7), 1.0, Vec3(0.0, 1.0, 0.0) }, // Green sphere
+        { Vec3(2, -1, 6), 1.0, Vec3(0.0, 0.0, 1.0) }  // Blue sphere
+    };
+    int numSpheres = sizeof(spheres) / sizeof(Sphere);
+    Vec3 lightPos(5, 5, 0);
+
+    unsigned char* d_framebuffer;
+    unsigned char* h_framebuffer = new unsigned char[WIDTH * HEIGHT * 3];
+    Sphere* d_spheres;
+    cudaMalloc(&d_framebuffer, WIDTH * HEIGHT * 3);
+    cudaMalloc(&d_spheres, numSpheres * sizeof(Sphere));
+    cudaMemcpy(d_spheres, spheres, numSpheres * sizeof(Sphere), cudaMemcpyHostToDevice);
+
+    dim3 threadsPerBlock(16, 16);
+    dim3 numBlocks((WIDTH + threadsPerBlock.x - 1) / threadsPerBlock.x, 
+                   (HEIGHT + threadsPerBlock.y - 1) / threadsPerBlock.y);
+    renderKernel<<<numBlocks, threadsPerBlock>>>(d_framebuffer, d_spheres, numSpheres, lightPos);
+    cudaDeviceSynchronize();
+
+    cudaMemcpy(h_framebuffer, d_framebuffer, WIDTH * HEIGHT * 3, cudaMemcpyDeviceToHost);
+    saveImage("output.ppm", h_framebuffer, WIDTH, HEIGHT);
+
+    cudaFree(d_framebuffer);
+    cudaFree(d_spheres);
+    delete[] h_framebuffer;
+
+    std::cout << "High-resolution image saved as output.ppm" << std::endl;
+    return 0;
+}