diff --git a/u07/main.c b/u07/main.c
index ea56b66..d3ce248 100644
--- a/u07/main.c
+++ b/u07/main.c
@@ -38,6 +38,9 @@ const GLfloat pi = 3.14159f;
 
 vec3 cameraPosition = {0.0f, 3.0f, 5.5f};
 
+char* defaultModel = "../obj/monkey.obj";
+char** model = &defaultModel;
+
 // input handler for camera movement
 void handleInputs(double deltaTime) {
 	if (glfwGetKey(window, GLFW_KEY_S) == GLFW_PRESS) {
@@ -132,7 +135,7 @@ void init(void) {
 
 
 	// --------------- READ teapot.obj
-	ParsedObjFile teapot = readObjFile("../obj/monkey.obj");
+	ParsedObjFile teapot = readObjFile(*model);
 	numFaces = teapot.length;
 
 	// write teapot faces to buffer
@@ -215,6 +218,7 @@ void draw(void) {
 	// counts up to 1.0 and then resets back to 0.0 forever
 	step += deltaTime / 5;
 	if (step > 1.0f) step -= 1.0f;
+	if (step < 0.0f) step += 1.0f;
 
 	// step multiplied by pi * 2 for use in rotation and trig functions
 	GLfloat stepi = step * pi * 2;
@@ -299,8 +303,11 @@ void framebuffer_size_callback(GLFWwindow *window, int width, int height) {
 	aspectRatio = (float)width / height;
 }
 
-int main(void) {
+int main(int argc, char **argv) {
 
+	if (argc == 2) {
+		model = &argv[1];
+	}
 	// initialise window
 	glfwInit();
 	glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);