diff --git a/tetris.c b/tetris.c
index aa5d426..c2e3c46 100644
--- a/tetris.c
+++ b/tetris.c
@@ -2,6 +2,8 @@
 #include <stdlib.h>
 #include <unistd.h>
 
+#include <ncurses.h>
+
 enum {
     HEIGHT = 20,
     WIDTH = 10,
@@ -18,7 +20,7 @@ struct rotation {
 
 struct brick {
     struct rotation *states;
-    int state;
+    int rotation;
     struct position position;
 };
 
@@ -63,13 +65,8 @@ struct rotation t_brick_rotations[4] = {
 
 };
 
-struct game_state {
-    char running;
-    char game_grid[WIDTH][HEIGHT];
-    struct brick current_brick;
-};
-
 enum input {
+    I_NONE,
     I_QUIT,
     I_LEFT,
     I_RIGHT,
@@ -77,29 +74,42 @@ enum input {
     I_ROTATE,
 };
 
+struct game_state {
+    char running;
+    char grid[WIDTH][HEIGHT];
+    struct brick current_brick;
+    enum input input;
+    unsigned int tick;
+};
+
 struct game_state construct_game_state();
 
 struct brick spawn_brick();
 
-/* gravitate brick (darf der das?) */
+int gravitate_brick(struct game_state *game_state);
 
 /* (optional) drop brick */
 
-/* should brick fall? */
-
-/* rotate brick */
-
 /* check for full line */
 
 /* remove full line */
 
-/* move brick */
+int brick_collides_x(struct brick brick);
 
-/* get input */
+int brick_collides_y(struct brick brick);
 
-/* evaluate input */
+int brick_collides_grid(struct brick brick, struct game_state game_state);
+
+void move_brick(struct brick *brick, int direction);
+
+void rotate_brick(struct brick *brick);
+
+enum input get_input();
+
+void evaluate_input(struct game_state *game_state, enum input input);
 
 /* brick to grid */
+void brick_to_grid(struct brick brick, struct game_state *game_state);
 
 /* loose condition */
 
@@ -108,22 +118,32 @@ void draw_game_state(struct game_state game_state);
 int brick_on_position(int x, int y, struct brick brick);
 
 int main(void) {
+    initscr();
+    noecho();
+    nodelay(stdscr, TRUE);
     struct game_state game_state = construct_game_state();
     while (game_state.running) {
+        game_state.tick++;
         draw_game_state(game_state);
-        //get input
-        //evaluate input
-        //game logic
-        game_state.current_brick.position.y++;
-        sleep(1);
+        enum input input = get_input();
+        evaluate_input(&game_state, input);
+        if (game_state.tick % 10 == 0) {
+            int brick_fell = gravitate_brick(&game_state);
+            if (!brick_fell) {
+                game_state.current_brick = spawn_brick();
+            }
+        }
+        usleep(100000);
     }
+    endwin();
 }
 
 struct game_state construct_game_state() {
     struct game_state game_state = {
         .running = 1,
-        .game_grid = {0},
-        .current_brick = spawn_brick()
+        .grid = {0},
+        .current_brick = spawn_brick(),
+        .tick = 0,
     };
     return game_state;
 }
@@ -131,37 +151,37 @@ struct game_state construct_game_state() {
 struct brick spawn_brick() {
     struct brick brick = {
         .states = t_brick_rotations,
-        .state = 0,
+        .rotation = 0,
         .position = {.x = 3, .y=0}
     };
     return brick;
 }
 
 void draw_game_state(struct game_state game_state) {
-    system("clear");
+    clear();
     for (int y = 0; y < HEIGHT; ++y) {
-        printf("|");
+        printw("|");
         for (int x = 0; x < WIDTH; ++x) {
-            if (game_state.game_grid[x][y]
+            if (game_state.grid[x][y]
                     || brick_on_position(x, y, game_state.current_brick)) {
-                printf("O");
+                printw("O");
             } else {
-                printf(" ");
+                printw(" ");
             }
         }
-        printf("|\n");
+        printw("|\n");
     }
-    printf("|");
+    printw("|");
     for (int x = 0; x < WIDTH; ++x) {
-        printf("-");
+        printw("-");
     }
-    printf("|\n");
+    printw("|\n");
 }
 
 int brick_on_position(int x, int y, struct brick brick) {
     x -= brick.position.x;
     y -= brick.position.y;
-    struct rotation *rotation = &brick.states[brick.state];
+    struct rotation *rotation = &brick.states[brick.rotation];
     for (int i = 0; i < 4; ++i) {
         if (rotation->tiles[i].x == x && rotation->tiles[i].y == y) {
             return 1;
@@ -169,3 +189,116 @@ int brick_on_position(int x, int y, struct brick brick) {
     }
     return 0;
 }
+
+enum input get_input() {
+    char in = getch();
+    switch (in) {
+        case 'w':
+            return I_ROTATE;
+        case 'q':
+            return I_QUIT;
+        case 'a':
+            return I_LEFT;
+        case 'd':
+            return I_RIGHT;
+        case 's':
+            return I_DROP;
+        default:
+            return I_NONE;
+    }
+}
+
+void evaluate_input(struct game_state *game_state, enum input input) {
+    switch (input) {
+        case I_ROTATE:
+            rotate_brick(&game_state->current_brick);
+            break;
+        case I_QUIT:
+            game_state->running = false;
+            break;
+        case I_LEFT:
+            move_brick(&game_state->current_brick, -1);
+            break;
+        case I_RIGHT:
+            move_brick(&game_state->current_brick, 1);
+            break;
+        case I_DROP:
+            while(gravitate_brick(game_state)) {
+                /* void */
+            }
+            break;
+        default:
+            break;
+    }
+}
+
+void rotate_brick(struct brick *brick) {
+    brick->rotation++;
+    brick->rotation %= 4;
+    if (brick_collides_x(*brick)) {
+        /* for real module, do +4 and -1 */
+        brick->rotation += 3;
+        brick->rotation %= 4;
+    }
+}
+
+void move_brick(struct brick *brick, int direction) {
+    brick->position.x += direction;
+    if (brick_collides_x(*brick)) {
+        brick->position.x -= direction;
+    }
+}
+
+int brick_collides_x(struct brick brick) {
+    for (int i = 0; i < 4; ++i) {
+        struct position tile_pos = brick.states[brick.rotation].tiles[i];
+        tile_pos.x += brick.position.x;
+        if (tile_pos.x > WIDTH - 1 || tile_pos.x < 0) {
+            return 1;
+        }
+    }
+    return 0;
+}
+
+int brick_collides_y(struct brick brick) {
+    for (int i = 0; i < 4; ++i) {
+        struct position tile_pos = brick.states[brick.rotation].tiles[i];
+        tile_pos.y += brick.position.y;
+        if (tile_pos.y > HEIGHT - 1) {
+            return 1;
+        }
+    }
+    return 0;
+}
+
+int brick_collides_grid(struct brick brick, struct game_state game_state) {
+    for (int i = 0; i < 4; ++i) {
+        struct position tile_pos = brick.states[brick.rotation].tiles[i];
+        tile_pos.x += brick.position.x;
+        tile_pos.y += brick.position.y;
+        if (game_state.grid[tile_pos.x][tile_pos.y]) {
+            return 1;
+        }
+    }
+    return 0;
+}
+
+int gravitate_brick(struct game_state *game_state) {
+    game_state->current_brick.position.y++;
+    if (brick_collides_grid(game_state->current_brick, *game_state)
+            || brick_collides_y(game_state->current_brick)) {
+        game_state->current_brick.position.y--;
+        brick_to_grid(game_state->current_brick, game_state);
+        return 0;
+    }
+    return 1;
+}
+
+void brick_to_grid(struct brick brick, struct game_state *game_state) {
+    for (int i = 0; i < 4; ++i) {
+        struct position tile_pos = brick.states[brick.rotation].tiles[i];
+        tile_pos.x += brick.position.x;
+        tile_pos.y += brick.position.y;
+        game_state->grid[tile_pos.x][tile_pos.y] = 1;
+    }
+}