diff --git a/src/cells.c b/src/cells.c
index 38c7e62..88632a0 100644
--- a/src/cells.c
+++ b/src/cells.c
@@ -27,4 +27,59 @@
 * For more information, please refer to <https://unlicense.org/>
 */
 
-#include <stdio.h>
\ No newline at end of file
+#include <stdio.h>
+#include "cells.h"
+#include "raylib.h"
+
+void drawGrid(int grid[CELL_AMOUNT][CELL_AMOUNT])
+{
+    for (size_t i=0; i<CELL_AMOUNT; i++)
+    {
+        for (size_t j=0; j<CELL_AMOUNT; j++)
+        {
+            if (grid[i][j] == VOID)
+            {
+                DrawRectangle(CELL_SIZE_PIXELS*j, CELL_SIZE_PIXELS*i, CELL_SIZE_PIXELS, CELL_SIZE_PIXELS, BLACK);
+            }
+            if (grid[i][j] == SAND)
+            {
+                DrawRectangle(CELL_SIZE_PIXELS*j, CELL_SIZE_PIXELS*i, CELL_SIZE_PIXELS, CELL_SIZE_PIXELS, MAROON);
+            }
+        }
+    }
+}
+
+void putCell(int grid[CELL_AMOUNT][CELL_AMOUNT], int posX, int posY)
+{
+    grid[posX][posY] = SAND;
+}
+
+void updateGrid(int grid[CELL_AMOUNT][CELL_AMOUNT])
+{
+    for (int i=CELL_AMOUNT-1; i>=0; i--)
+    {
+        for (int j=0; j<CELL_AMOUNT; j++)
+        {
+            switch (grid[i][j])
+            {
+                case VOID:
+                    break;
+                case SAND:
+                    if (i+1 < CELL_AMOUNT && grid[i+1][j] == VOID) {
+                        grid[i][j] = VOID;
+                        grid[i+1][j] = SAND; // falling downwards
+                    } else if (i+1 < CELL_AMOUNT && j+1 < CELL_AMOUNT && grid[i+1][j+1] == VOID) {
+                        grid[i][j] = VOID;
+                        grid[i+1][j+1] = SAND; // falling down-right
+                    }
+                    else if (i+1 < CELL_AMOUNT && j-1 >= 0 && grid[i+1][j-1] == VOID) {
+                        grid[i][j] = VOID;
+                        grid[i+1][j-1] = SAND; // falling down-left
+                    }
+                    break;
+                default:
+                    break;
+            }
+        }
+    }
+}
\ No newline at end of file
diff --git a/src/cells.h b/src/cells.h
index ccea4d5..4bb364e 100644
--- a/src/cells.h
+++ b/src/cells.h
@@ -30,4 +30,26 @@
 #ifndef CELLS_H
 #define CELLS_H
 
+#define CELL_AMOUNT         80
+#define CELL_SIZE_PIXELS    10
+#define TARGET_FPS          60
+
+#define WINDOW_SIZE_PIXELS  (CELL_AMOUNT * CELL_SIZE_PIXELS)
+
+typedef enum GameScreen 
+{
+    TITLE,
+    GAME
+} GameScreen;
+
+typedef enum CellType
+{
+    VOID,
+    SAND
+} CellType;
+
+void drawGrid(int grid[CELL_AMOUNT][CELL_AMOUNT]);
+void putCell(int grid[CELL_AMOUNT][CELL_AMOUNT], int posX, int posY);
+void updateGrid(int grid[CELL_AMOUNT][CELL_AMOUNT]);
+
 #endif // CELLS_H
\ No newline at end of file
diff --git a/src/main.c b/src/main.c
index ef646da..a21d585 100644
--- a/src/main.c
+++ b/src/main.c
@@ -32,18 +32,58 @@
 
 int main ()
 {
+	int grid[CELL_AMOUNT][CELL_AMOUNT] = {0};
+	GameScreen currentScreen = TITLE;
+
 	SetConfigFlags(FLAG_VSYNC_HINT | FLAG_WINDOW_HIGHDPI);
-	InitWindow(1280, 800, "Sandbox");
+	InitWindow(WINDOW_SIZE_PIXELS, WINDOW_SIZE_PIXELS, "Sandbox");
+	SetTargetFPS(TARGET_FPS);
 	
 	// game loop
 	while (!WindowShouldClose())
 	{
-		test();
-		// drawing
-		BeginDrawing();
+		/* Update */
+		switch (currentScreen)
+		{
+			case TITLE:
+				if (IsKeyPressed(KEY_SPACE)) {
+					currentScreen = GAME;
+					ClearBackground(BLACK);
+				}
+				break;
+			case GAME:
+				if (IsMouseButtonDown(MOUSE_BUTTON_LEFT)) {
+					Vector2 cellPosition = GetMousePosition();
+					int i = cellPosition.y/CELL_SIZE_PIXELS;
+					int j = cellPosition.x/CELL_SIZE_PIXELS;
+					putCell(grid, i, j);
+				}
+				break;
+			default:
+				break;
+		}
 
-		// Setup the back buffer for drawing (clear color and depth buffers)
-		ClearBackground(BLACK);
+		/* Drawing */
+		BeginDrawing();
+		switch (currentScreen)
+		{
+			case TITLE:
+				int titleWidth = MeasureText("SANDBOX", 40);
+				DrawRectangle(0, 0, WINDOW_SIZE_PIXELS, WINDOW_SIZE_PIXELS, DARKBLUE);
+				DrawText("SANDBOX", (WINDOW_SIZE_PIXELS-titleWidth)/2, 20, 40, WHITE);
+				int controlsWidth = MeasureText("Controls", 30);
+				DrawText("Controls", (WINDOW_SIZE_PIXELS-controlsWidth)/2, 100, 30, WHITE);
+				DrawText("Left click to spawn sand", 25, 150, 30, WHITE);
+				int startGameWidth = MeasureText("Press Space to start!", 30);
+				DrawText("Press Space to start!", (WINDOW_SIZE_PIXELS-startGameWidth)/2, 400, 30, WHITE);
+				break;
+			case GAME:
+				updateGrid(grid);
+				drawGrid(grid);
+				break;
+			default:
+				break;
+		}
 		
 		// end the frame and get ready for the next one  (display frame, poll input, etc...)
 		EndDrawing();