diff --git a/engine/Matrix4x4.cpp b/engine/Matrix4x4.cpp
index 2f02ed9..541a668 100644
--- a/engine/Matrix4x4.cpp
+++ b/engine/Matrix4x4.cpp
@@ -37,15 +37,10 @@ Vec3D Matrix4x4::operator*(const Vec3D &vec) const {
 Matrix4x4 Matrix4x4::Identity() {
     Matrix4x4 result;
 
-    for (int i = 0; i < 4; i++) {
-        for (int j = 0; j < 4; j++) {
-            if (i == j) {
-                result._arr[j][i] = 1.0;
-            } else {
-                result._arr[j][i] = 0.0;
-            }
-        }
-    }
+    result._arr[0][0] = 1.0;
+    result._arr[1][1] = 1.0;
+    result._arr[2][2] = 1.0;
+    result._arr[3][3] = 1.0;
 
     return result;
 }
@@ -93,12 +88,15 @@ Matrix4x4 Matrix4x4::Translation(const Vec3D &v) {
 
 Matrix4x4 Matrix4x4::RotationX(double rx) {
     Matrix4x4 Rx{};
+
+    double c = cos(rx), s = sin(rx);
+
     Rx._arr[0][0] = 1.0;
 
-    Rx._arr[1][1] = cos(rx);
-    Rx._arr[1][2] = -sin(rx);
-    Rx._arr[2][1] = sin(rx);
-    Rx._arr[2][2] = cos(rx);
+    Rx._arr[1][1] = c;
+    Rx._arr[1][2] = -s;
+    Rx._arr[2][1] = s;
+    Rx._arr[2][2] = c;
 
     Rx._arr[3][3] = 1.0;
 
@@ -108,12 +106,14 @@ Matrix4x4 Matrix4x4::RotationX(double rx) {
 Matrix4x4 Matrix4x4::RotationY(double ry) {
     Matrix4x4 Ry{};
 
+    double c = cos(ry), s = sin(ry);
+
     Ry._arr[1][1] = 1.0;
 
-    Ry._arr[0][0] = cos(ry);
-    Ry._arr[0][2] = sin(ry);
-    Ry._arr[2][0] = -sin(ry);
-    Ry._arr[2][2] = cos(ry);
+    Ry._arr[0][0] = c;
+    Ry._arr[0][2] = s;
+    Ry._arr[2][0] = -s;
+    Ry._arr[2][2] = c;
 
     Ry._arr[3][3] = 1.0;
 
@@ -123,12 +123,14 @@ Matrix4x4 Matrix4x4::RotationY(double ry) {
 Matrix4x4 Matrix4x4::RotationZ(double rz) {
     Matrix4x4 Rz{};
 
+    double c = cos(rz), s = sin(rz);
+
     Rz._arr[2][2] = 1.0;
 
-    Rz._arr[0][0] = cos(rz);
-    Rz._arr[0][1] = -sin(rz);
-    Rz._arr[1][0] = sin(rz);
-    Rz._arr[1][1] = cos(rz);
+    Rz._arr[0][0] = c;
+    Rz._arr[0][1] = -s;
+    Rz._arr[1][0] = s;
+    Rz._arr[1][1] = c;
 
     Rz._arr[3][3] = 1.0;
 
@@ -143,17 +145,19 @@ Matrix4x4 Matrix4x4::Rotation(const Vec3D &v, double rv) {
     Matrix4x4 Rv{};
     Vec3D nv(v.normalized());
 
-    Rv._arr[0][0] = cos(rv) + (1.0 - cos(rv)) * nv.x() * nv.x();
-    Rv._arr[0][1] = (1.0 - cos(rv)) * nv.x() * nv.y() - sin(rv) * nv.z();
-    Rv._arr[0][2] = (1.0 - cos(rv)) * nv.x() * nv.z() + sin(rv) * nv.y();
+    double c = cos(rv), s = sin(rv);
 
-    Rv._arr[1][0] = (1.0 - cos(rv)) * nv.x() * nv.y() + sin(rv) * nv.z();
-    Rv._arr[1][1] = cos(rv) + (1.0 - cos(rv)) * nv.y() * nv.y();
-    Rv._arr[1][2] = (1.0 - cos(rv)) * nv.y() * nv.z() - sin(rv) * nv.x();
+    Rv._arr[0][0] = c + (1.0 - c) * nv.x() * nv.x();
+    Rv._arr[0][1] = (1.0 - c) * nv.x() * nv.y() - s * nv.z();
+    Rv._arr[0][2] = (1.0 - c) * nv.x() * nv.z() + s * nv.y();
 
-    Rv._arr[2][0] = (1.0 - cos(rv)) * nv.z() * nv.x() - sin(rv) * nv.y();
-    Rv._arr[2][1] = (1.0 - cos(rv)) * nv.z() * nv.y() + sin(rv) * nv.x();
-    Rv._arr[2][2] = cos(rv) + (1.0 - cos(rv)) * nv.z() * nv.z();
+    Rv._arr[1][0] = (1.0 - c) * nv.x() * nv.y() + s * nv.z();
+    Rv._arr[1][1] = c + (1.0 - c) * nv.y() * nv.y();
+    Rv._arr[1][2] = (1.0 - c) * nv.y() * nv.z() - s * nv.x();
+
+    Rv._arr[2][0] = (1.0 - c) * nv.z() * nv.x() - s * nv.y();
+    Rv._arr[2][1] = (1.0 - c) * nv.z() * nv.y() + s * nv.x();
+    Rv._arr[2][2] = c + (1.0 - c) * nv.z() * nv.z();
 
     Rv._arr[3][3] = 1.0;
 
diff --git a/engine/Vec2D.cpp b/engine/Vec2D.cpp
index ef0fd37..4305a8d 100644
--- a/engine/Vec2D.cpp
+++ b/engine/Vec2D.cpp
@@ -39,7 +39,7 @@ Vec2D Vec2D::operator+(const Vec2D &vec) const {
 }
 
 Vec2D Vec2D::operator-(const Vec2D &vec) const {
-    return Vec2D(*this) + -vec;
+    return *this + -vec;
 }
 
 Vec2D Vec2D::operator*(double number) const {
@@ -48,7 +48,7 @@ Vec2D Vec2D::operator*(double number) const {
 
 Vec2D Vec2D::operator/(double number) const {
     if (std::abs(number) > Consts::EPS) {
-        return Vec2D(*this) * (1.0 / number);
+        return *this * (1.0 / number);
     } else {
         throw std::domain_error{"Vec2D::operator/(double number): division by zero"};
     }
@@ -64,9 +64,9 @@ double Vec2D::abs() const {
 }
 
 Vec2D Vec2D::normalized() const {
-    double vecAbs = abs();
+    double vecAbs = sqrAbs();
     if (vecAbs > Consts::EPS) {
-        return Vec2D(*this) / vecAbs;
+        return *this / sqrt(vecAbs);
     } else {
         return Vec2D(0);
     }
diff --git a/engine/Vec3D.cpp b/engine/Vec3D.cpp
index 3a41ca4..349c9a8 100644
--- a/engine/Vec3D.cpp
+++ b/engine/Vec3D.cpp
@@ -44,7 +44,7 @@ Vec3D Vec3D::operator+(const Vec3D &vec) const {
 }
 
 Vec3D Vec3D::operator-(const Vec3D &vec) const {
-    return Vec3D(*this) + -vec;
+    return *this + -vec;
 }
 
 Vec3D Vec3D::operator*(double number) const {
@@ -53,7 +53,7 @@ Vec3D Vec3D::operator*(double number) const {
 
 Vec3D Vec3D::operator/(double number) const {
     if (std::abs(number) > Consts::EPS) {
-        return Vec3D(*this) * (1.0 / number);
+        return *this * (1.0 / number);
     } else {
         throw std::domain_error{"Vec3D::operator/(double number): division by zero"};
     }
@@ -69,9 +69,9 @@ double Vec3D::abs() const {
 }
 
 Vec3D Vec3D::normalized() const {
-    double vecAbs = abs();
+    double vecAbs = sqrAbs();
     if (vecAbs > Consts::EPS) {
-        return Vec3D(*this) / vecAbs;
+        return *this / sqrt(vecAbs);
     } else {
         return Vec3D(1);
     }
diff --git a/engine/Vec4D.cpp b/engine/Vec4D.cpp
index f9a92a6..b11321a 100644
--- a/engine/Vec4D.cpp
+++ b/engine/Vec4D.cpp
@@ -40,7 +40,7 @@ Vec4D Vec4D::operator+(const Vec4D &point4D) const {
 }
 
 Vec4D Vec4D::operator-(const Vec4D &point4D) const {
-    return Vec4D(*this) + -point4D;
+    return *this + -point4D;
 }
 
 Vec4D Vec4D::operator*(double number) const {
@@ -49,7 +49,7 @@ Vec4D Vec4D::operator*(double number) const {
 
 Vec4D Vec4D::operator/(double number) const {
     if (std::abs(number) > Consts::EPS) {
-        return Vec4D(*this) * (1.0 / number);
+        return *this * (1.0 / number);
     } else {
         throw std::domain_error{"Vec4D::operator/(double number): division by zero"};
     }
@@ -65,9 +65,9 @@ double Vec4D::abs() const {
 }
 
 Vec4D Vec4D::normalized() const {
-    double vecAbs = abs();
+    double vecAbs = sqrAbs();
     if (vecAbs > Consts::EPS) {
-        return Vec4D(*this) / vecAbs;
+        return *this / sqrt(vecAbs);
     } else {
         return Vec4D(1);
     }