diff --git a/cosets/CMakeLists.txt b/cosets/CMakeLists.txt
index c8cf75b..5a14367 100644
--- a/cosets/CMakeLists.txt
+++ b/cosets/CMakeLists.txt
@@ -6,14 +6,14 @@ add_executable(${PROJECT_NAME}
 target_link_libraries(${PROJECT_NAME}
         PRIVATE glad glm glfw)
 
-target_include_directories(${PROJECT_NAME}
-        PRIVATE include)
-
 add_custom_command(
-    TARGET cosets POST_BUILD
-    COMMAND ${CMAKE_COMMAND} -E copy_directory
-            ${CMAKE_CURRENT_SOURCE_DIR}/src/shaders
-            ${CMAKE_CURRENT_BINARY_DIR}/shaders
+        TARGET cosets POST_BUILD
+        COMMAND ${CMAKE_COMMAND} -E copy_directory
+        ${CMAKE_CURRENT_SOURCE_DIR}/src/shaders
+        ${CMAKE_CURRENT_BINARY_DIR}/shaders
 )
 
 add_executable(coxeter src/tc.cpp)
+
+add_executable(mirror src/mirror.cpp)
+target_link_libraries(mirror PRIVATE glm)
diff --git a/cosets/src/mirror.cpp b/cosets/src/mirror.cpp
new file mode 100644
index 0000000..098e5c4
--- /dev/null
+++ b/cosets/src/mirror.cpp
@@ -0,0 +1,48 @@
+#include <cmath>
+#include <vector>
+#include <iostream>
+#include <glm/glm.hpp>
+#include <glm/gtx/string_cast.hpp>
+#include <iomanip>
+
+#include "util/numeric.hpp"
+
+template<int N>
+std::vector<glm::vec4> mirror(const float (&arr)[N][N]) {
+   static_assert(1 <= N and N <= 4, "Vector size is unsupported");
+
+   std::vector<glm::vec4> mirrors{};
+   for (int p = 0; p < N; ++p) {
+      glm::vec4 vp{};
+      for (int m = 0; m < p; ++m) {
+         glm::vec4 vq = mirrors[m];
+         vp[m] = (cos(M_PI / arr[p][m]) - dot(m, vp, vq)) / vq[m];
+      }
+      vp[p] = std::sqrt(1 - glm::dot(vp, vp));
+
+      for (const auto &v : mirrors) {
+         if (glm::dot(vp, v) > 0) {
+            vp *= -1;
+            break;
+         }
+      }
+
+      mirrors.push_back(round(vp, 15));
+   }
+
+   return mirrors;
+}
+
+int main(int argc, char *argv[]) {
+   auto normals = mirror<3>({
+      {},
+      {4},
+      {2, 3}
+   });
+
+   for (const auto &normal : normals) {
+      std::cout << glm::to_string(normal) << std::endl;
+   }
+
+   return 0;
+}
\ No newline at end of file
diff --git a/cosets/src/tc.cpp b/cosets/src/tc.cpp
index 4db7b3b..013714e 100644
--- a/cosets/src/tc.cpp
+++ b/cosets/src/tc.cpp
@@ -98,7 +98,7 @@ struct Row {
       this->to = cos;
    }
 
-   bool learn(Table *table) {
+   [[nodiscard]] bool learn(Table *table) {
       if (r - l == 0) {
          return false;
       }
diff --git a/cosets/src/util/numeric.hpp b/cosets/src/util/numeric.hpp
new file mode 100644
index 0000000..b4ab66c
--- /dev/null
+++ b/cosets/src/util/numeric.hpp
@@ -0,0 +1,17 @@
+#pragma once
+
+#include <glm/glm.hpp>
+
+glm::vec4 round(glm::vec4 f, int prec) {
+   auto dec = (float) pow(10, prec);
+   auto res = glm::trunc(f * dec + 0.5f) / dec;
+   return res;
+}
+
+float dot(int n, glm::vec4 a, glm::vec4 b) {
+   float sum = 0;
+   for (int i = 0; i < n; ++i) {
+      sum += a[i] * b[i];
+   }
+   return sum;
+}