diff --git a/Makefile b/Makefile
index f431d83..7fe459a 100644
--- a/Makefile
+++ b/Makefile
@@ -16,6 +16,7 @@ EXAMPLES = \
 	example/riemman \
 	example/n-cube \
 	example/n-hilbert-cube \
+	example/light-cone \
 	example/lens
 
 CFLAGS = \
diff --git a/example/basic.c b/example/basic.c
index 0488340..50fadd2 100644
--- a/example/basic.c
+++ b/example/basic.c
@@ -34,7 +34,7 @@ void mobius(float *d_surface, int *coord, unsigned char *grid)
 
 void torus(float *d_surface, int *coord, unsigned char *grid)
 {
-	float u = (2 * M_PI) * ((float)coord[0] / grid[0]);
+	float u = (M_PI) * ((float)coord[0] / grid[0]) + M_PI;
 	float v = (2 * M_PI) * ((float)coord[1] / grid[1]);
 
 	d_surface[0] = (1 + 0.5 * cos(v)) * cos(u);
@@ -57,12 +57,14 @@ int main(void)
 {
 	unsigned char i = 0;
 	const char *file_name[] = {"mobius.klein", "torus.klein", "klein.klein"};
-	struct parm parametrization[] = {{
-										 .grid = (unsigned char[]){16, 4},
-										 .m = 2,
-										 .n = 3,
-										 .f = mobius,
-									 },
+	struct parm parametrization[] = {
+		{
+			 .grid = (unsigned char[]){16, 4},
+
+			 .m = 2,
+			 .n = 3,
+			 .f = mobius,
+		 },
 		{
 			.grid = (unsigned char[]){16, 8},
 			.m = 2,
@@ -74,9 +76,10 @@ int main(void)
 			.m = 2,
 			.n = 4,
 			.f = klein,
-		}};
+		},
+	};
 
-	for (i = 0; i < 3; ++i)
+	for (i = 0; i < 4; ++i)
 	{
 		struct klein klein;
 		printf("writing %s\n", file_name[i]);
diff --git a/src/input.c b/src/input.c
index 9a4f60e..835d158 100644
--- a/src/input.c
+++ b/src/input.c
@@ -187,6 +187,28 @@ quat_t poll_input(window_t window)
 		goto end;
 	}
 
+	if (glfwGetKey((GLFWwindow *)window, GLFW_KEY_UP) == GLFW_PRESS)
+	{
+		glm_quatv(p, ANGLE, (vec3){1,0,0});
+		goto end;
+	}
+	if (glfwGetKey((GLFWwindow *)window, GLFW_KEY_DOWN) == GLFW_PRESS)
+	{
+		glm_quatv(p, -ANGLE, (vec3){1,0,0});
+		goto end;
+	}
+	if (glfwGetKey((GLFWwindow *)window, GLFW_KEY_RIGHT) == GLFW_PRESS)
+	{
+		glm_quatv(p, ANGLE, (vec3){0,1,0});
+		goto end;
+	}
+	if (glfwGetKey((GLFWwindow *)window, GLFW_KEY_LEFT) == GLFW_PRESS)
+	{
+
+		glm_quatv(p, -ANGLE, (vec3){0,1,0});
+		goto end;
+	}
+
 end:
 	glm_quat_mul(p, q, q);
 	glm_quat_rotatev(p, axis[0], axis[0]);
diff --git a/src/klein.c b/src/klein.c
index 7c01494..3a40edf 100644
--- a/src/klein.c
+++ b/src/klein.c
@@ -1,5 +1,6 @@
 #include "main.h"
 
+#include <stdlib.h>
 #include <stdio.h>
 
 /*
diff --git a/src/mesh.c b/src/mesh.c
index 1ad14ad..f9a0e28 100644
--- a/src/mesh.c
+++ b/src/mesh.c
@@ -106,6 +106,7 @@ void draw_mesh_lines(id_t shader, mesh_t p)
 {
 	struct obj *obj = p;
 
+	glLineWidth(4);
 	glUseProgram(shader);
 	glBindVertexArray(obj->vao);
 #ifndef EMSCRIPTEN