diff --git a/inc/forza4.h b/inc/forza4.h
index 35efa20..ff8d86c 100644
--- a/inc/forza4.h
+++ b/inc/forza4.h
@@ -3,12 +3,22 @@
 
 #include <structures.h>
 
-static int col;
+#define ORIZONTAL       1
+#define VERTICAL        _COLLUMS
+#define DIAGONAL        _COLLUMS - 1
+#define DIAGONAL_INV    _COLLUMS + 1
+
+#define isValid(pos) (pos > 0 && pos / _COLLUMS < _ROWS)
+
+// global variable
+static int _ROWS;
+static int _COLLUMS;
+
 
 void setCollums(int collums);
 int getIndex(int i, int j);
 
-tile_t checkWin(tile_t *board, int pos, int rows, int collums);
-tile_t checkWinAll(tile_t *board, int rows, int collums);
+int checkWin(tile_t *board, int pos, int rows, int collums);
+int checkWinAll(tile_t *board, int rows, int collums);
 
 #endif
\ No newline at end of file
diff --git a/src/forza4.c b/src/forza4.c
index c68480d..9b6f713 100644
--- a/src/forza4.c
+++ b/src/forza4.c
@@ -1,73 +1,63 @@
 #include <stdio.h>
+#include <forza4.h>
 
 #include <structures.h>
 
-static int col;
+void setCollums(int rows) {
+	_ROWS = rows;
+}
 
 void setCollums(int collums) {
-	col = collums;
+	_COLLUMS = collums;
 }
 
 int getIndex(int r, int c) {
-	return r * col + c;
+	return r * _COLLUMS + c;
 }
 
+int checkLine(tile_t *board, int pos, int delta) {
+	int count = 1, i;
+	i = pos - delta;
+	while (isValid(i) && board[pos] == board[i]) {
+		count++;
+		i -= delta;
+	}
+	i = pos + delta;
+	while (isValid(i) && board[pos] == board[i]) {
+		count++;
+		i += delta;
+	}
+
+	return count >= 4;
+} 
+
 // checks board for a win
 // returns player tile_t on win, otherwise 0
-tile_t checkWin(tile_t *board, int pos, int rows, int collums) {
-	int i;
-
-	tile_t current = board[pos];
-	int r = pos / collums;
-	int c = pos % collums;
-
-	for (i=0; i<4; i++) {
-
-		// vertical
-		if (r + i - 3 >= 0 && r + i < rows) {
-			if (board[getIndex(r + i - 3, c)] == board[getIndex(r + i, c)] &&
-				board[getIndex(r + i - 2, c)] == board[getIndex(r + i, c)] &&
-				board[getIndex(r + i - 1, c)] == board[getIndex(r + i, c)]) {
-			
-				return current;
-			}
-		}
-
-		// horizontal
-		if (c + i - 3 >= 0 && c + i < collums) {
-			if (board[getIndex(r, c + i - 3)] == board[getIndex(r, c + i)] &&
-				board[getIndex(r, c + i - 2)] == board[getIndex(r, c + i)] &&
-				board[getIndex(r, c + i - 1)] == board[getIndex(r, c + i)]) {
-			
-				return current;
-			}
-		}
-
-		// diagonal1
-		if (c + i - 3 >= 0 && c + i < collums && r + i - 3 >= 0 && r + i < rows) {
-			if (board[getIndex(r + i - 3, c + i - 3)] == board[getIndex(r + i, c + i)] &&
-				board[getIndex(r + i - 2, c + i - 2)] == board[getIndex(r + i, c + i)] &&
-				board[getIndex(r + i - 1, c + i - 1)] == board[getIndex(r + i, c + i)]) {
-			
-				return current;
-			}
-		}
-
-		// diagonal2
-		if (c + i + 3 >= 0 && c + i < collums && r - i + 3 < rows && r - i >= 0) {
-			if (board[getIndex(r - i + 3, c + i - 3)] == board[getIndex(r - i, c + i)] &&
-				board[getIndex(r - i + 2, c + i - 2)] == board[getIndex(r - i, c + i)] &&
-				board[getIndex(r - i + 1, c + i - 1)] == board[getIndex(r - i, c + i)]) {
-			
-				return current;
-			}
-		}
+int checkWin(tile_t *board, int pos, int rows, int collums) {
+	int result = checkLine(board, pos, ORIZONTAL); 
+	if (result) {
+		return board[pos];
 	}
-	
-	return EMPTY;
+
+	int result = checkLine(board, pos, VERTICAL); 
+	if (result) {
+		return board[pos];
+	}
+
+	int result = checkLine(board, pos, DIAGONAL); 
+	if (result) {
+		return board[pos];
+	}
+
+	int result = checkLine(board, pos, DIAGONAL_INV); 
+	if (result) {
+		return board[pos];
+	}
+
+	return 0;
 }
 
-tile_t checkWinAll(tile_t *board, int rows, int collums){
+int checkWinAll(tile_t *board, int rows, int collums){
 	for (int i=0; i<rows*collums; i++) {
 		if (checkWin(board, i, rows, collums) != EMPTY) {
 			return checkWin(board, i, rows, collums);