diff --git a/libs/main/containers/pivector2d.h b/libs/main/containers/pivector2d.h
index 7bd8a990..809277e8 100644
--- a/libs/main/containers/pivector2d.h
+++ b/libs/main/containers/pivector2d.h
@@ -193,7 +193,6 @@ public:
 		//! \~russian Преобразует строку в \a PIVector.
 		inline PIVector<T> toVector() const { return PIVector<T>(p_->data(st_), sz_); }
 
-		// --- Поиск в строке ---
 		inline ssize_t indexOf(const T & e, ssize_t start = 0) const {
 			if (start < 0) start = 0;
 			for (size_t i = (size_t)start; i < sz_; ++i) {
@@ -201,6 +200,7 @@ public:
 			}
 			return -1;
 		}
+
 		inline ssize_t lastIndexOf(const T & e, ssize_t start = -1) const {
 			ssize_t from = (start < 0 || (size_t)start >= sz_) ? (ssize_t)sz_ - 1 : start;
 			for (ssize_t i = from; i >= 0; --i) {
@@ -208,6 +208,7 @@ public:
 			}
 			return -1;
 		}
+
 		inline ssize_t indexWhere(std::function<bool(const T & e)> test, ssize_t start = 0) const {
 			if (start < 0) start = 0;
 			for (size_t i = (size_t)start; i < sz_; ++i) {
@@ -215,6 +216,7 @@ public:
 			}
 			return -1;
 		}
+
 		inline ssize_t lastIndexWhere(std::function<bool(const T & e)> test, ssize_t start = -1) const {
 			ssize_t from = (start < 0 || (size_t)start >= sz_) ? (ssize_t)sz_ - 1 : start;
 			for (ssize_t i = from; i >= 0; --i) {
@@ -222,6 +224,74 @@ public:
 			}
 			return -1;
 		}
+
+		//! \~english Applies a function to each element of the row (modifiable).
+		//! \~russian Применяет функцию к каждому элементу строки (с возможностью изменения).
+		inline void forEach(std::function<void(T &)> func) {
+			for (size_t i = 0; i < sz_; ++i) {
+				func((*p_)[st_ + i]);
+			}
+		}
+
+		//! \~english Applies a function to each element of the row (read-only).
+		//! \~russian Применяет функцию к каждому элементу строки (только чтение).
+		inline void forEach(std::function<void(const T &)> func) const {
+			for (size_t i = 0; i < sz_; ++i) {
+				func((*p_)[st_ + i]);
+			}
+		}
+
+		//! \~english Fills the row with copies of `value`.
+		//! \~russian Заполняет строку копиями `value`.
+		inline void fill(const T & value) {
+			for (size_t i = 0; i < sz_; ++i) {
+				(*p_)[st_ + i] = value;
+			}
+		}
+
+		//! \~english Checks if the row contains the element `e`.
+		//! \~russian Проверяет, содержит ли строка элемент `e`.
+		inline bool contains(const T & e, ssize_t start = 0) const { return indexOf(e, start) != -1; }
+
+		//! \~english Counts occurrences of `e` in the row.
+		//! \~russian Подсчитывает количество вхождений `e` в строке.
+		inline int entries(const T & e, ssize_t start = 0) const {
+			if (start < 0) start = 0;
+			int count = 0;
+			for (size_t i = (size_t)start; i < sz_; ++i) {
+				if ((*p_)[st_ + i] == e) ++count;
+			}
+			return count;
+		}
+
+		//! \~english Counts elements in the row that pass the `test`.
+		//! \~russian Подсчитывает элементы в строке, проходящие `test`.
+		inline int entries(std::function<bool(const T & e)> test, ssize_t start = 0) const {
+			if (start < 0) start = 0;
+			int count = 0;
+			for (size_t i = (size_t)start; i < sz_; ++i) {
+				if (test((*p_)[st_ + i])) ++count;
+			}
+			return count;
+		}
+
+		//! \~english Tests if any element in the row passes the `test`.
+		//! \~russian Проверяет, проходит ли какой-либо элемент в строке `test`.
+		inline bool any(std::function<bool(const T & e)> test) const {
+			for (size_t i = 0; i < sz_; ++i) {
+				if (test((*p_)[st_ + i])) return true;
+			}
+			return false;
+		}
+
+		//! \~english Tests if all elements in the row pass the `test`.
+		//! \~russian Проверяет, проходят ли все элементы в строке `test`.
+		inline bool every(std::function<bool(const T & e)> test) const {
+			for (size_t i = 0; i < sz_; ++i) {
+				if (!test((*p_)[st_ + i])) return false;
+			}
+			return true;
+		}
 	};
 
 	//! \class Col
@@ -290,7 +360,6 @@ public:
 			return ret;
 		}
 
-		// --- Поиск в столбце ---
 		inline ssize_t indexOf(const T & e, ssize_t start = 0) const {
 			if (start < 0) start = 0;
 			for (size_t i = (size_t)start; i < sz_; ++i) {
@@ -298,6 +367,7 @@ public:
 			}
 			return -1;
 		}
+
 		inline ssize_t lastIndexOf(const T & e, ssize_t start = -1) const {
 			ssize_t from = (start < 0 || (size_t)start >= sz_) ? (ssize_t)sz_ - 1 : start;
 			for (ssize_t i = from; i >= 0; --i) {
@@ -305,6 +375,7 @@ public:
 			}
 			return -1;
 		}
+
 		inline ssize_t indexWhere(std::function<bool(const T & e)> test, ssize_t start = 0) const {
 			if (start < 0) start = 0;
 			for (size_t i = (size_t)start; i < sz_; ++i) {
@@ -312,6 +383,7 @@ public:
 			}
 			return -1;
 		}
+
 		inline ssize_t lastIndexWhere(std::function<bool(const T & e)> test, ssize_t start = -1) const {
 			ssize_t from = (start < 0 || (size_t)start >= sz_) ? (ssize_t)sz_ - 1 : start;
 			for (ssize_t i = from; i >= 0; --i) {
@@ -319,6 +391,74 @@ public:
 			}
 			return -1;
 		}
+
+		//! \~english Applies a function to each element of the column (modifiable).
+		//! \~russian Применяет функцию к каждому элементу столбца (с возможностью изменения).
+		inline void forEach(std::function<void(T &)> func) {
+			for (size_t i = 0; i < sz_; ++i) {
+				func((*p_)[i * step_ + col_]);
+			}
+		}
+
+		//! \~english Applies a function to each element of the column (read-only).
+		//! \~russian Применяет функцию к каждому элементу столбца (только чтение).
+		inline void forEach(std::function<void(const T &)> func) const {
+			for (size_t i = 0; i < sz_; ++i) {
+				func((*p_)[i * step_ + col_]);
+			}
+		}
+
+		//! \~english Fills the column with copies of `value`.
+		//! \~russian Заполняет столбец копиями `value`.
+		inline void fill(const T & value) {
+			for (size_t i = 0; i < sz_; ++i) {
+				(*p_)[i * step_ + col_] = value;
+			}
+		}
+
+		//! \~english Checks if the column contains the element `e`.
+		//! \~russian Проверяет, содержит ли столбец элемент `e`.
+		inline bool contains(const T & e, ssize_t start = 0) const { return indexOf(e, start) != -1; }
+
+		//! \~english Counts occurrences of `e` in the column.
+		//! \~russian Подсчитывает количество вхождений `e` в столбце.
+		inline int entries(const T & e, ssize_t start = 0) const {
+			if (start < 0) start = 0;
+			int count = 0;
+			for (size_t i = (size_t)start; i < sz_; ++i) {
+				if ((*p_)[i * step_ + col_] == e) ++count;
+			}
+			return count;
+		}
+
+		//! \~english Counts elements in the column that pass the `test`.
+		//! \~russian Подсчитывает элементы в столбце, проходящие `test`.
+		inline int entries(std::function<bool(const T & e)> test, ssize_t start = 0) const {
+			if (start < 0) start = 0;
+			int count = 0;
+			for (size_t i = (size_t)start; i < sz_; ++i) {
+				if (test((*p_)[i * step_ + col_])) ++count;
+			}
+			return count;
+		}
+
+		//! \~english Tests if any element in the column passes the `test`.
+		//! \~russian Проверяет, проходит ли какой-либо элемент в столбце `test`.
+		inline bool any(std::function<bool(const T & e)> test) const {
+			for (size_t i = 0; i < sz_; ++i) {
+				if (test((*p_)[i * step_ + col_])) return true;
+			}
+			return false;
+		}
+
+		//! \~english Tests if all elements in the column pass the `test`.
+		//! \~russian Проверяет, проходят ли все элементы в столбце `test`.
+		inline bool every(std::function<bool(const T & e)> test) const {
+			for (size_t i = 0; i < sz_; ++i) {
+				if (!test((*p_)[i * step_ + col_])) return false;
+			}
+			return true;
+		}
 	};
 
 	//! \class RowConst
@@ -353,7 +493,6 @@ public:
 		//! \~russian Преобразует строку в \a PIVector.
 		inline PIVector<T> toVector() const { return PIVector<T>(p_->data(st_), sz_); }
 
-		// --- Поиск в строке (только чтение) ---
 		inline ssize_t indexOf(const T & e, ssize_t start = 0) const {
 			if (start < 0) start = 0;
 			for (size_t i = (size_t)start; i < sz_; ++i) {
@@ -361,6 +500,7 @@ public:
 			}
 			return -1;
 		}
+
 		inline ssize_t lastIndexOf(const T & e, ssize_t start = -1) const {
 			ssize_t from = (start < 0 || (size_t)start >= sz_) ? (ssize_t)sz_ - 1 : start;
 			for (ssize_t i = from; i >= 0; --i) {
@@ -368,6 +508,7 @@ public:
 			}
 			return -1;
 		}
+
 		inline ssize_t indexWhere(std::function<bool(const T & e)> test, ssize_t start = 0) const {
 			if (start < 0) start = 0;
 			for (size_t i = (size_t)start; i < sz_; ++i) {
@@ -375,6 +516,7 @@ public:
 			}
 			return -1;
 		}
+
 		inline ssize_t lastIndexWhere(std::function<bool(const T & e)> test, ssize_t start = -1) const {
 			ssize_t from = (start < 0 || (size_t)start >= sz_) ? (ssize_t)sz_ - 1 : start;
 			for (ssize_t i = from; i >= 0; --i) {
@@ -382,6 +524,58 @@ public:
 			}
 			return -1;
 		}
+
+		//! \~english Applies a function to each element of the row (read-only).
+		//! \~russian Применяет функцию к каждому элементу строки (только чтение).
+		inline void forEach(std::function<void(const T &)> func) const {
+			for (size_t i = 0; i < sz_; ++i) {
+				func((*p_)[st_ + i]);
+			}
+		}
+
+		//! \~english Checks if the row contains the element `e`.
+		//! \~russian Проверяет, содержит ли строка элемент `e`.
+		inline bool contains(const T & e, ssize_t start = 0) const { return indexOf(e, start) != -1; }
+
+		//! \~english Counts occurrences of `e` in the row.
+		//! \~russian Подсчитывает количество вхождений `e` в строке.
+		inline int entries(const T & e, ssize_t start = 0) const {
+			if (start < 0) start = 0;
+			int count = 0;
+			for (size_t i = (size_t)start; i < sz_; ++i) {
+				if ((*p_)[st_ + i] == e) ++count;
+			}
+			return count;
+		}
+
+		//! \~english Counts elements in the row that pass the `test`.
+		//! \~russian Подсчитывает элементы в строке, проходящие `test`.
+		inline int entries(std::function<bool(const T & e)> test, ssize_t start = 0) const {
+			if (start < 0) start = 0;
+			int count = 0;
+			for (size_t i = (size_t)start; i < sz_; ++i) {
+				if (test((*p_)[st_ + i])) ++count;
+			}
+			return count;
+		}
+
+		//! \~english Tests if any element in the row passes the `test`.
+		//! \~russian Проверяет, проходит ли какой-либо элемент в строке `test`.
+		inline bool any(std::function<bool(const T & e)> test) const {
+			for (size_t i = 0; i < sz_; ++i) {
+				if (test((*p_)[st_ + i])) return true;
+			}
+			return false;
+		}
+
+		//! \~english Tests if all elements in the row pass the `test`.
+		//! \~russian Проверяет, проходят ли все элементы в строке `test`.
+		inline bool every(std::function<bool(const T & e)> test) const {
+			for (size_t i = 0; i < sz_; ++i) {
+				if (!test((*p_)[st_ + i])) return false;
+			}
+			return true;
+		}
 	};
 
 	//! \class ColConst
@@ -423,7 +617,6 @@ public:
 			return ret;
 		}
 
-		// --- Поиск в столбце (только чтение) ---
 		inline ssize_t indexOf(const T & e, ssize_t start = 0) const {
 			if (start < 0) start = 0;
 			for (size_t i = (size_t)start; i < sz_; ++i) {
@@ -431,6 +624,7 @@ public:
 			}
 			return -1;
 		}
+
 		inline ssize_t lastIndexOf(const T & e, ssize_t start = -1) const {
 			ssize_t from = (start < 0 || (size_t)start >= sz_) ? (ssize_t)sz_ - 1 : start;
 			for (ssize_t i = from; i >= 0; --i) {
@@ -438,6 +632,7 @@ public:
 			}
 			return -1;
 		}
+
 		inline ssize_t indexWhere(std::function<bool(const T & e)> test, ssize_t start = 0) const {
 			if (start < 0) start = 0;
 			for (size_t i = (size_t)start; i < sz_; ++i) {
@@ -445,6 +640,7 @@ public:
 			}
 			return -1;
 		}
+
 		inline ssize_t lastIndexWhere(std::function<bool(const T & e)> test, ssize_t start = -1) const {
 			ssize_t from = (start < 0 || (size_t)start >= sz_) ? (ssize_t)sz_ - 1 : start;
 			for (ssize_t i = from; i >= 0; --i) {
@@ -452,6 +648,58 @@ public:
 			}
 			return -1;
 		}
+
+		//! \~english Applies a function to each element of the column (read-only).
+		//! \~russian Применяет функцию к каждому элементу столбца (только чтение).
+		inline void forEach(std::function<void(const T &)> func) const {
+			for (size_t i = 0; i < sz_; ++i) {
+				func((*p_)[i * step_ + col_]);
+			}
+		}
+
+		//! \~english Checks if the column contains the element `e`.
+		//! \~russian Проверяет, содержит ли столбец элемент `e`.
+		inline bool contains(const T & e, ssize_t start = 0) const { return indexOf(e, start) != -1; }
+
+		//! \~english Counts occurrences of `e` in the column.
+		//! \~russian Подсчитывает количество вхождений `e` в столбце.
+		inline int entries(const T & e, ssize_t start = 0) const {
+			if (start < 0) start = 0;
+			int count = 0;
+			for (size_t i = (size_t)start; i < sz_; ++i) {
+				if ((*p_)[i * step_ + col_] == e) ++count;
+			}
+			return count;
+		}
+
+		//! \~english Counts elements in the column that pass the `test`.
+		//! \~russian Подсчитывает элементы в столбце, проходящие `test`.
+		inline int entries(std::function<bool(const T & e)> test, ssize_t start = 0) const {
+			if (start < 0) start = 0;
+			int count = 0;
+			for (size_t i = (size_t)start; i < sz_; ++i) {
+				if (test((*p_)[i * step_ + col_])) ++count;
+			}
+			return count;
+		}
+
+		//! \~english Tests if any element in the column passes the `test`.
+		//! \~russian Проверяет, проходит ли какой-либо элемент в столбце `test`.
+		inline bool any(std::function<bool(const T & e)> test) const {
+			for (size_t i = 0; i < sz_; ++i) {
+				if (test((*p_)[i * step_ + col_])) return true;
+			}
+			return false;
+		}
+
+		//! \~english Tests if all elements in the column pass the `test`.
+		//! \~russian Проверяет, проходят ли все элементы в столбце `test`.
+		inline bool every(std::function<bool(const T & e)> test) const {
+			for (size_t i = 0; i < sz_; ++i) {
+				if (!test((*p_)[i * step_ + col_])) return false;
+			}
+			return true;
+		}
 	};
 
 	//! \~english Returns a reference to the element at the given row and column.
diff --git a/tests/math/testpivector2d.cpp b/tests/math/testpivector2d.cpp
index 538348d7..aef6c86b 100644
--- a/tests/math/testpivector2d.cpp
+++ b/tests/math/testpivector2d.cpp
@@ -993,6 +993,243 @@ TEST(Vector2DEdgeTest, single_element_vector) {
 	EXPECT_EQ(single.element(0, 0), 42);
 }
 
+// ==================== PROXY ADDITIONAL OPERATIONS TESTS ====================
+TEST_F(Vector2DTest, row_proxy_forEach_modifies_elements) {
+	auto row = vec[5];
+	row.forEach([](int & e) { e += 100; });
+	for (size_t c = 0; c < COLS_COUNT_INIT; ++c) {
+		EXPECT_EQ(vec.element(5, c), 5 * COLS_COUNT_INIT + c + 100);
+	}
+}
+
+TEST_F(Vector2DTest, row_proxy_forEach_const_iterates) {
+	const auto & constVec = vec;
+	auto row              = constVec[5];
+	size_t count          = 0;
+	row.forEach([&count](const int &) { ++count; });
+	EXPECT_EQ(count, COLS_COUNT_INIT);
+}
+
+TEST_F(Vector2DTest, row_proxy_fill_sets_all_elements) {
+	auto row = vec[12];
+	row.fill(999);
+	for (size_t c = 0; c < COLS_COUNT_INIT; ++c) {
+		EXPECT_EQ(vec.element(12, c), 999);
+	}
+}
+
+TEST_F(Vector2DTest, row_proxy_contains_finds_element) {
+	auto row = vec[8];
+	EXPECT_TRUE(row.contains(vec.element(8, 10)));
+	EXPECT_FALSE(row.contains(-999));
+}
+
+TEST_F(Vector2DTest, row_proxy_entries_counts_occurrences) {
+	auto row            = vec[15];
+	// Add a duplicate
+	int val             = vec.element(15, 5);
+	vec.element(15, 20) = val;
+	EXPECT_EQ(row.entries(val), 2);
+	EXPECT_EQ(row.entries(-999), 0);
+}
+
+TEST_F(Vector2DTest, row_proxy_entries_with_predicate_counts_matches) {
+	auto row     = vec[20];
+	auto isEven  = [](const int & e) { return e % 2 == 0; };
+	int expected = 0;
+	for (size_t c = 0; c < COLS_COUNT_INIT; ++c) {
+		if (row[c] % 2 == 0) ++expected;
+	}
+	EXPECT_EQ(row.entries(isEven), expected);
+}
+
+TEST_F(Vector2DTest, row_proxy_any_returns_true_if_any_match) {
+	auto row        = vec[25];
+	auto isNegative = [](const int & e) { return e < 0; };
+	EXPECT_FALSE(row.any(isNegative));
+	auto isPositive = [](const int & e) { return e >= 0; };
+	EXPECT_TRUE(row.any(isPositive));
+}
+
+TEST_F(Vector2DTest, row_proxy_every_returns_true_if_all_match) {
+	auto row           = vec[30];
+	auto isLessThanMax = [&](const int & e) { return e < static_cast<int>(vec.size()); };
+	EXPECT_TRUE(row.every(isLessThanMax));
+	auto isEven = [](const int & e) { return e % 2 == 0; };
+	EXPECT_FALSE(row.every(isEven));
+}
+
+// ----------------------------------------------------------------------------
+TEST_F(Vector2DTest, col_proxy_forEach_modifies_elements) {
+	auto col = vec.col(7);
+	col.forEach([](int & e) { e += 50; });
+	for (size_t r = 0; r < ROWS_COUNT_INIT; ++r) {
+		EXPECT_EQ(vec.element(r, 7), r * COLS_COUNT_INIT + 7 + 50);
+	}
+}
+
+TEST_F(Vector2DTest, col_proxy_forEach_const_iterates) {
+	const auto & constVec = vec;
+	auto col              = constVec.col(9);
+	size_t count          = 0;
+	col.forEach([&count](const int &) { ++count; });
+	EXPECT_EQ(count, ROWS_COUNT_INIT);
+}
+
+TEST_F(Vector2DTest, col_proxy_fill_sets_all_elements) {
+	auto col = vec.col(11);
+	col.fill(777);
+	for (size_t r = 0; r < ROWS_COUNT_INIT; ++r) {
+		EXPECT_EQ(vec.element(r, 11), 777);
+	}
+}
+
+TEST_F(Vector2DTest, col_proxy_contains_finds_element) {
+	auto col = vec.col(13);
+	EXPECT_TRUE(col.contains(vec.element(5, 13)));
+	EXPECT_FALSE(col.contains(-999));
+}
+
+TEST_F(Vector2DTest, col_proxy_entries_counts_occurrences) {
+	auto col            = vec.col(17);
+	int val             = vec.element(3, 17);
+	vec.element(22, 17) = val; // duplicate
+	EXPECT_EQ(col.entries(val), 2);
+	EXPECT_EQ(col.entries(-999), 0);
+}
+
+TEST_F(Vector2DTest, col_proxy_entries_with_predicate_counts_matches) {
+	auto col     = vec.col(19);
+	auto isOdd   = [](const int & e) { return e % 2 != 0; };
+	int expected = 0;
+	for (size_t r = 0; r < ROWS_COUNT_INIT; ++r) {
+		if (col[r] % 2 != 0) ++expected;
+	}
+	EXPECT_EQ(col.entries(isOdd), expected);
+}
+
+TEST_F(Vector2DTest, col_proxy_any_returns_true_if_any_match) {
+	auto col        = vec.col(21);
+	auto isNegative = [](const int & e) { return e < 0; };
+	EXPECT_FALSE(col.any(isNegative));
+	auto isPositive = [](const int & e) { return e >= 0; };
+	EXPECT_TRUE(col.any(isPositive));
+}
+
+TEST_F(Vector2DTest, col_proxy_every_returns_true_if_all_match) {
+	auto col           = vec.col(23);
+	auto isLessThanMax = [&](const int & e) { return e < static_cast<int>(vec.size()); };
+	EXPECT_TRUE(col.every(isLessThanMax));
+	auto isEven = [](const int & e) { return e % 2 == 0; };
+	EXPECT_FALSE(col.every(isEven));
+}
+
+// ----------------------------------------------------------------------------
+TEST_F(Vector2DTest, rowconst_proxy_forEach_iterates) {
+	const auto & constVec = vec;
+	auto row              = constVec[5];
+	size_t count          = 0;
+	row.forEach([&count](const int &) { ++count; });
+	EXPECT_EQ(count, COLS_COUNT_INIT);
+}
+
+TEST_F(Vector2DTest, rowconst_proxy_contains_finds_element) {
+	const auto & constVec = vec;
+	auto row              = constVec[6];
+	EXPECT_TRUE(row.contains(vec.element(6, 10)));
+	EXPECT_FALSE(row.contains(-999));
+}
+
+TEST_F(Vector2DTest, rowconst_proxy_entries_counts_occurrences) {
+	const auto & constVec = vec;
+	auto row              = constVec[7];
+	int val               = vec.element(7, 5);
+	// We can't modify through const proxy, but duplicates already exist from previous tests
+	EXPECT_GE(row.entries(val), 1); // at least one
+}
+
+TEST_F(Vector2DTest, rowconst_proxy_entries_with_predicate_counts_matches) {
+	const auto & constVec = vec;
+	auto row              = constVec[9];
+	auto isEven           = [](const int & e) { return e % 2 == 0; };
+	int expected          = 0;
+	for (size_t c = 0; c < COLS_COUNT_INIT; ++c) {
+		if (vec.element(9, c) % 2 == 0) ++expected;
+	}
+	EXPECT_EQ(row.entries(isEven), expected);
+}
+
+TEST_F(Vector2DTest, rowconst_proxy_any_returns_true_if_any_match) {
+	const auto & constVec = vec;
+	auto row              = constVec[10];
+	auto isNegative       = [](const int & e) { return e < 0; };
+	EXPECT_FALSE(row.any(isNegative));
+	auto isPositive = [](const int & e) { return e >= 0; };
+	EXPECT_TRUE(row.any(isPositive));
+}
+
+TEST_F(Vector2DTest, rowconst_proxy_every_returns_true_if_all_match) {
+	const auto & constVec = vec;
+	auto row              = constVec[11];
+	auto isLessThanMax    = [&](const int & e) { return e < static_cast<int>(vec.size()); };
+	EXPECT_TRUE(row.every(isLessThanMax));
+	auto isEven = [](const int & e) { return e % 2 == 0; };
+	EXPECT_FALSE(row.every(isEven));
+}
+
+// ----------------------------------------------------------------------------
+TEST_F(Vector2DTest, colconst_proxy_forEach_iterates) {
+	const auto & constVec = vec;
+	auto col              = constVec.col(25);
+	size_t count          = 0;
+	col.forEach([&count](const int &) { ++count; });
+	EXPECT_EQ(count, ROWS_COUNT_INIT);
+}
+
+TEST_F(Vector2DTest, colconst_proxy_contains_finds_element) {
+	const auto & constVec = vec;
+	auto col              = constVec.col(27);
+	EXPECT_TRUE(col.contains(vec.element(4, 27)));
+	EXPECT_FALSE(col.contains(-999));
+}
+
+TEST_F(Vector2DTest, colconst_proxy_entries_counts_occurrences) {
+	const auto & constVec = vec;
+	auto col              = constVec.col(29);
+	int val               = vec.element(8, 29);
+	EXPECT_GE(col.entries(val), 1);
+}
+
+TEST_F(Vector2DTest, colconst_proxy_entries_with_predicate_counts_matches) {
+	const auto & constVec = vec;
+	auto col              = constVec.col(31);
+	auto isOdd            = [](const int & e) { return e % 2 != 0; };
+	int expected          = 0;
+	for (size_t r = 0; r < ROWS_COUNT_INIT; ++r) {
+		if (vec.element(r, 31) % 2 != 0) ++expected;
+	}
+	EXPECT_EQ(col.entries(isOdd), expected);
+}
+
+TEST_F(Vector2DTest, colconst_proxy_any_returns_true_if_any_match) {
+	const auto & constVec = vec;
+	auto col              = constVec.col(33);
+	auto isNegative       = [](const int & e) { return e < 0; };
+	EXPECT_FALSE(col.any(isNegative));
+	auto isPositive = [](const int & e) { return e >= 0; };
+	EXPECT_TRUE(col.any(isPositive));
+}
+
+TEST_F(Vector2DTest, colconst_proxy_every_returns_true_if_all_match) {
+	const auto & constVec = vec;
+	auto col              = constVec.col(0);
+	auto isLessThanMax    = [&](const int & e) { return e < static_cast<int>(vec.size()); };
+	EXPECT_TRUE(col.every(isLessThanMax));
+	auto isNotEven = [](const int & e) { return e % 2 != 0; };
+	col.forEach([](const int & v) { piCout << v; });
+	EXPECT_FALSE(col.every(isNotEven));
+}
+
 // ==================== OUTPUT TESTS ====================
 TEST_F(Vector2DTest, picout_operator_works) {
 	// Just test that it compiles and doesn't crash