diff --git a/F1-nolib/Tetris/TETRIS.bin b/F1-nolib/Tetris/TETRIS.bin
index f795364..5ba973d 100755
Binary files a/F1-nolib/Tetris/TETRIS.bin and b/F1-nolib/Tetris/TETRIS.bin differ
diff --git a/F1-nolib/Tetris/balls.c b/F1-nolib/Tetris/balls.c
index 5e4a796..bb8e535 100644
--- a/F1-nolib/Tetris/balls.c
+++ b/F1-nolib/Tetris/balls.c
@@ -41,7 +41,7 @@ static int
     xspeed[NBALLSMAX], yspeed[NBALLSMAX];
 static uint8_t colr[NBALLSMAX];
 static int Nballs = 0;
-static uint32_t Tlast, Taddb;
+static uint32_t TlastB, Taddb;
 
 static void clear_balls(){
     for(int i = 0; i < Nballs; ++i)
@@ -70,21 +70,21 @@ static void add_ball(){
 
 void balls_init(){
     Nballs = 0;
-    setBGcolor(0);
+    setBGcolor(COLOR_BLACK);
     ClearScreen();
     ScreenON();
-    Tlast = Tms;
+    TlastB = Tms;
     add_ball();
 }
 
 //#define abs(x)  ((x<0) ? -x : x)
 
 void process_balls(){
-    if(Tms == Tlast) return;
+    if(Tms == TlastB) return;
     if(Nballs < NBALLSMAX && Taddb < Tms){
         add_ball();
     }
-    int diff = (int)(Tms - Tlast);
+    int diff = (int)(Tms - TlastB);
     for(int i = 0; i < Nballs; ++i){
         xnew[i] = x[i] + xspeed[i]*diff;
         ynew[i] = y[i] + yspeed[i]*diff;
@@ -104,5 +104,5 @@ void process_balls(){
     }
     clear_balls();
     draw_balls();
-    Tlast = Tms;
+    TlastB = Tms;
 }
diff --git a/F1-nolib/Tetris/buttons.c b/F1-nolib/Tetris/buttons.c
index bf71536..20e267b 100644
--- a/F1-nolib/Tetris/buttons.c
+++ b/F1-nolib/Tetris/buttons.c
@@ -22,6 +22,7 @@
 #include "hardware.h"
 
 extern volatile uint32_t Tms;
+uint32_t lastUnsleep = 0;
 
 // threshold in ms for press/hold
 #define PRESSTHRESHOLD  (9)
@@ -54,6 +55,7 @@ void process_keys(){
         keybase *k = &allkeys[i];
         keyevent e = k->event;
         if(PRESSED(k->port, k->pin)){ // key is in pressed state
+            lastUnsleep = Tms; // update activity time (any key is in pressed state)
             switch(e){
                 case EVT_NONE: // just pressed
                 case EVT_RELEASE:
diff --git a/F1-nolib/Tetris/buttons.h b/F1-nolib/Tetris/buttons.h
index f5eba8b..1d3d99a 100644
--- a/F1-nolib/Tetris/buttons.h
+++ b/F1-nolib/Tetris/buttons.h
@@ -43,6 +43,8 @@ typedef enum{
     EVT_RELEASE // released
 } keyevent;
 
+extern uint32_t lastUnsleep; // last keys activity time
+
 void process_keys();
 void clear_events();
 uint8_t keystate(keycode k, keyevent *evt);
diff --git a/F1-nolib/Tetris/main.c b/F1-nolib/Tetris/main.c
index e6edc85..1a9a559 100644
--- a/F1-nolib/Tetris/main.c
+++ b/F1-nolib/Tetris/main.c
@@ -25,9 +25,13 @@
 #include "proto.h"
 #include "screen.h"
 #include "snake.h"
+#include "tetris.h"
 #include "usb.h"
 #include "usb_lib.h"
 
+// timeout for autosleep (30s)
+#define AUTOSLEEP_TMOUT     (30000)
+
 volatile uint32_t Tms = 0;
 uint8_t balls = 0;
 
@@ -35,7 +39,8 @@ enum{
     STATE_MENU,
     STATE_SNAKE,
     STATE_TETRIS,
-    STATE_SLEEP
+    STATE_SLEEP,
+    STATE_GAMEOVER
 } curstate = STATE_SLEEP;
 
 /* Called when systick fires */
@@ -89,6 +94,8 @@ static void process_menu(){
         break;
         case MENU_TETRIS:
             USB_send("Select 'Tetris'\n");
+            tetris_init();
+            curstate = STATE_TETRIS;
         break;
         default:
         break;
@@ -112,7 +119,7 @@ int main(void){
     USBPU_OFF();
     adc_setup();
     USB_setup();
-    iwdg_setup();
+    //iwdg_setup();
     USBPU_ON();
 
     keyevent evt;
@@ -133,12 +140,32 @@ int main(void){
             break;
             case STATE_MENU:
                 process_menu();
+                if(Tms - lastUnsleep > AUTOSLEEP_TMOUT){
+                    USB_send("Autosleep\n");
+                    ScreenOFF();
+                    curstate = STATE_SLEEP;
+                }
             break;
             case STATE_SNAKE:
-                if(!proces_snake()) gotomenu();
+                if(!snake_proces()){
+                    show_gameover();
+                    curstate = STATE_GAMEOVER;
+                }
             break;
             case STATE_TETRIS:
-                ;
+                if(!tetris_process()){
+                    show_gameover();
+                    curstate = STATE_GAMEOVER;
+                }
+            break;
+            case STATE_GAMEOVER: // show gameover screen
+                if(keystate(KEY_M, &evt) && evt == EVT_RELEASE){
+                    gotomenu();
+                }else if(Tms - lastUnsleep > AUTOSLEEP_TMOUT){
+                    USB_send("Autosleep\n");
+                    ScreenOFF();
+                    curstate = STATE_SLEEP;
+                }
             break;
         }
 
diff --git a/F1-nolib/Tetris/menu.c b/F1-nolib/Tetris/menu.c
index 0bc7069..ef83ab6 100644
--- a/F1-nolib/Tetris/menu.c
+++ b/F1-nolib/Tetris/menu.c
@@ -39,13 +39,12 @@ static const char* items[] = {
     [MENU_TETRIS] = " Tetris "
 };
 
-
 static menuitem curitem = MENU_SLEEP;
 
 // show menu
 static void _menu(){
     choose_font(FONT14);
-    setBGcolor(0);
+    setBGcolor(COLOR_BLACK);
     ClearScreen();
     int charH = curfont->height, charB = curfont->baseline;
     int curI = midNo;
@@ -60,8 +59,7 @@ static void _menu(){
             setBGcolor(MENUBGCOLOR);
             setFGcolor(MENUFGCOLOR);
         }
-        PutStringAt((SCREEN_WIDTH - strpixlen(items[i]))/2,
-                    midY + (i-curI)*charH - charB, items[i]);
+        CenterStringAt(midY + (i-curI)*charH - charB, items[i]);
     }
 }
 
@@ -89,3 +87,15 @@ menuitem menu_activated(){
     clear_events(); // clear all other events
     return MENU_NONE;
 }
+
+// show "GAME OVER" screen
+void show_gameover(){
+    setBGcolor(COLOR_BLACK);
+    setFGcolor(COLOR_RED);
+    ClearScreen();
+    choose_font(FONT14);
+    CenterStringAt(SCREEN_HEIGHT/2 - curfont->baseline - 1, "Game Over!");
+    setFGcolor(COLOR_YELLOW);
+    uint8_t l = PutStringAt(0, SCREEN_HEIGHT - curfont->baseline, "Score: ");
+    PutStringAt(l, SCREEN_HEIGHT - curfont->baseline, u2str(score));
+}
diff --git a/F1-nolib/Tetris/menu.h b/F1-nolib/Tetris/menu.h
index 1273845..8ac68a9 100644
--- a/F1-nolib/Tetris/menu.h
+++ b/F1-nolib/Tetris/menu.h
@@ -19,6 +19,8 @@
 #ifndef MENU_H__
 #define MENU_H__
 
+#include <stm32f1.h>
+
 typedef enum{
     MENU_SLEEP,
     MENU_BALLS,
@@ -29,6 +31,7 @@ typedef enum{
 } menuitem;
 
 void show_menu();
+void show_gameover();
 menuitem menu_activated();
 
 
diff --git a/F1-nolib/Tetris/screen.c b/F1-nolib/Tetris/screen.c
index abec1be..10481f2 100644
--- a/F1-nolib/Tetris/screen.c
+++ b/F1-nolib/Tetris/screen.c
@@ -23,15 +23,17 @@
 #include "screen.h"
 //#include "usb.h"
 
-
 // !!!FOR LITTLE-ENDIAN!!!
 
+uint32_t score = 0;  // current game's score
+uint32_t StepMS, Tlast, incSpd = 0; // common for all games timer values
+
 // X coordinate - from left to right!
 // Y coordinate - from top to bottom!
 // (0,0) is top left corner
 
 // all-screen buffer
-static uint8_t screenbuf[SCREENBUF_SZ];
+uint8_t screenbuf[SCREENBUF_SZ];
 extern volatile uint32_t Tms; // time for FPS count
 static uint32_t FPS = 0, Tfps = 0; // approx FPS
 uint32_t getFPS(){return FPS;}
@@ -112,6 +114,17 @@ uint8_t PutStringAt(int16_t X, int16_t Y, const char *str){
     return X - Xold;
 }
 
+/**
+ * @brief CenterStringAt - draw string @ center line
+ * @param Y   - y coordinate
+ * @param str - string
+ * @return - text width in pixels
+ */
+uint8_t CenterStringAt(int16_t Y, const char *str){
+    int l = strpixlen(str);
+    return PutStringAt((SCREEN_WIDTH - l)/2, Y, str);
+}
+
 // full string length in pixels
 int strpixlen(const char *str){
     int l = 0;
@@ -122,8 +135,6 @@ int strpixlen(const char *str){
     return l;
 }
 
-uint8_t *getScreenBuf(){return screenbuf;}
-
 static screen_state ScrnState = SCREEN_RELAX;
 screen_state getScreenState(){return ScrnState;}
 
diff --git a/F1-nolib/Tetris/screen.h b/F1-nolib/Tetris/screen.h
index 7d4c4cd..6ded8e8 100644
--- a/F1-nolib/Tetris/screen.h
+++ b/F1-nolib/Tetris/screen.h
@@ -43,6 +43,23 @@ typedef enum{ // screen states
     SCREEN_UPDATENXT    // update next quarter
 } screen_state;
 
+// colors
+#define COLOR_BLACK     (0b00000000)
+#define COLOR_WHITE     (0b11111111)
+#define COLOR_BLUE      (0b00000011)
+#define COLOR_LBLUE     (0b00000001)
+#define COLOR_GREEN     (0b00011100)
+#define COLOR_LGREEN    (0b00001100)
+#define COLOR_RED       (0b11100000)
+#define COLOR_LRED      (0b01100000)
+#define COLOR_CYAN      (0b00011111)
+#define COLOR_PURPLE    (0b11100011)
+#define COLOR_YELLOW    (0b11111100)
+
+extern uint32_t score; // current game score
+extern uint8_t screenbuf[SCREENBUF_SZ];
+extern uint32_t StepMS, Tlast, incSpd; // common for all games timer values
+
 screen_state getScreenState();
 void ClearScreen();
 void setBGcolor(uint8_t c);
@@ -53,6 +70,7 @@ void XORPix(int16_t X, int16_t Y, uint8_t pix);
 uint8_t GetPix(int16_t X, int16_t Y);
 uint8_t DrawCharAt(int16_t X, int16_t Y, uint8_t Char);
 uint8_t PutStringAt(int16_t X, int16_t Y, const char *str);
+uint8_t CenterStringAt(int16_t Y, const char *str);
 int strpixlen(const char *str);
 uint8_t *getScreenBuf();
 void process_screen();
diff --git a/F1-nolib/Tetris/snake.c b/F1-nolib/Tetris/snake.c
index a36514e..b98995b 100644
--- a/F1-nolib/Tetris/snake.c
+++ b/F1-nolib/Tetris/snake.c
@@ -29,7 +29,19 @@
 #define SNAKE_BGCOLOR       (0)
 #define SNAKE_HEADCOLOR     (0b00001101)
 #define SNAKE_COLOR         (0b00101100)
+// food: +1 to size
 #define FOOD_COLOR          (0b00011100)
+// cut - -1 to size
+#define CUT_COLOR           (0b11100000)
+// chance of CUT appears  when drawing food (/1000)
+#define CUT_PROMILLE        (33)
+// score - +10 to score
+#define SCORE_COLOR         (0b00000001)
+// add this to score after each SCORE_COLOR eating
+#define ADDSCORE            (25)
+// chance of SCORE appears when doing move (1/1000)
+#define SCORE_PROMILLE      (15)
+// border
 #define BORDER_COLOR        (0b00100000)
 // max and min pause between steps
 #define MAXSTEPMS           (199)
@@ -46,24 +58,28 @@ static point snake[SNAKE_MAXLEN];
 static int8_t dirX, dirY;
 static uint8_t snakelen;
 static point Food;
-static uint32_t StepMS, Tlast, incSpd = 0;
-static uint32_t score;
 
-static void ThrowFood(){
-    int notfound = 1;
-    do{
-        Food.x = 1 + getRand() % (SCREEN_WIDTH-2);
-        Food.y = 1 + getRand() % (SCREEN_HEIGHT-2);
-        for(int i = 0; i < snakelen; ++i){
-            if(Food.x != snake[i].x && Food.y != snake[i].y){
-                notfound = 0;
-                break;
-            }
-        }
-    }while(notfound);
-    USB_send("Food @ "); USB_send(u2str(Food.x));
-    USB_send(", "); USB_send(u2str(Food.y)); USB_send("\n");
+static point RandCoords(){
+    point pt = {0,0};
+    for(int i = 0; i < 10000; ++i){ // not more than 10000 tries
+        pt.x = 1 + getRand() % (SCREEN_WIDTH-2);
+        pt.y = 1 + getRand() % (SCREEN_HEIGHT-2);
+        if(GetPix(pt.x, pt.y) == SNAKE_BGCOLOR) break;
+    };
+    return pt;
+}
+
+// return 0 if failed
+static int ThrowFood(){
+    Food = RandCoords();
+    if(Food.x == 0 && Food.y == 0) return 0;
     DrawPix(Food.x, Food.y, FOOD_COLOR);
+    if(getRand() % 1000 < CUT_PROMILLE){
+        point p = RandCoords();
+        if(p.x == 0 && p.y == 0) return 1;
+        DrawPix(p.x, p.y, CUT_COLOR);
+    }
+    return 1;
 }
 /*
 static void draw_snake(){
@@ -101,7 +117,6 @@ void snake_init(){
             dirX = 1; dirY = 0;
         break;
         case 1:
-
             dirX = -1; dirY = 0;
         break;
         case 2:
@@ -115,12 +130,14 @@ void snake_init(){
     Tlast = Tms; incSpd = 0;
     score = 0;
     DrawPix(snake[0].x, snake[0].y, SNAKE_HEADCOLOR);
+    USB_send("Snake inited\n");
 }
 
 // return 0 if failed
 static int move_snake(){
     int last = snakelen - 1;
     point tail = {snake[last].x, snake[last].y};
+    DrawPix(Food.x, Food.y, FOOD_COLOR); // redraw food
     DrawPix(snake[0].x, snake[0].y, SNAKE_COLOR); // redraw head with body color
     DrawPix(tail.x, tail.y, SNAKE_BGCOLOR); // delete tail
     for(int i = snakelen-1; i > 0; --i){
@@ -135,6 +152,11 @@ static int move_snake(){
             if(nxtcolr == SNAKE_COLOR) USB_send("slum into yourself\n");
             else USB_send("crush into border\n");
             return 0;
+        }else if(nxtcolr == CUT_COLOR && snakelen > 1){ // make snake shorter
+            --snakelen;
+            DrawPix(snake[snakelen].x, snake[snakelen].y, SNAKE_BGCOLOR);
+        }else if(nxtcolr == SCORE_COLOR){ // add score
+            score += ADDSCORE;
         }
         // not border or snake -> FOOD?!
         if(snake[0].x == Food.x && snake[0].y == Food.y){ // increase snake len & speed & score
@@ -145,7 +167,7 @@ static int move_snake(){
                 ++snakelen;
                 DrawPix(tail.x, tail.y, SNAKE_COLOR);
             }
-            ThrowFood();
+            if(!ThrowFood()) return 0;
             USB_send("Got food, score="); USB_send(u2str(score));
             USB_send(", len="); USB_send(u2str(snakelen));
             USB_send(", speed="); USB_send(u2str(StepMS));
@@ -163,7 +185,7 @@ static int move_snake(){
 #define DECRSPD()           do{incSpd /= 2;}while(0)
 
 // return 0 if game over
-int proces_snake(){
+int snake_proces(){
     keyevent evt;
     static uint8_t paused = 0;
     // change moving direction
@@ -173,13 +195,13 @@ int proces_snake(){
     if(keystate(KEY_D, &evt)){ // Down
         if(evt == EVT_PRESS){ if(dirY != -1) SETDIR(0, 1);}
     }
-    if(keystate(KEY_L, &evt)){ // Down
+    if(keystate(KEY_L, &evt)){ // Left
         if(evt == EVT_PRESS){ if(dirX != 1) SETDIR(-1, 0);}
     }
-    if(keystate(KEY_R, &evt) && (evt == EVT_PRESS || evt == EVT_HOLD)){ // Down
+    if(keystate(KEY_R, &evt) && (evt == EVT_PRESS || evt == EVT_HOLD)){ // Right
         if(evt == EVT_PRESS){ if(dirX != -1) SETDIR(1, 0);}
     }
-    if(keystate(KEY_M, &evt) && (evt == EVT_PRESS || evt == EVT_HOLD)){ // Pause or out
+    if(keystate(KEY_M, &evt) && (evt == EVT_PRESS || evt == EVT_HOLD)){ // Menu - Pause or out
         if(3 == ++paused){
             USB_send("Exit snake\n");
             clear_events();
@@ -187,7 +209,7 @@ int proces_snake(){
             return 0;
         }
     }
-    if(keystate(KEY_S, &evt) && (evt == EVT_PRESS || evt == EVT_HOLD)){ // Pause
+    if(keystate(KEY_S, &evt) && (evt == EVT_PRESS || evt == EVT_HOLD)){ // Set - Pause
         if(paused){
             USB_send("Snake resume\n");
             paused = 0;
@@ -226,4 +248,3 @@ int proces_snake(){
     return 1;
 }
 
-uint32_t snake_getscore(){return score;}
diff --git a/F1-nolib/Tetris/snake.h b/F1-nolib/Tetris/snake.h
index 6b9e3a3..603ab2c 100644
--- a/F1-nolib/Tetris/snake.h
+++ b/F1-nolib/Tetris/snake.h
@@ -19,10 +19,7 @@
 #ifndef SNAKE_H__
 #define SNAKE_H__
 
-#include <stm32f1.h>
-
 void snake_init();
-int proces_snake();
-uint32_t snake_getscore();
+int snake_proces();
 
 #endif // SNAKE_H__
diff --git a/F1-nolib/Tetris/tetris.c b/F1-nolib/Tetris/tetris.c
new file mode 100644
index 0000000..951c876
--- /dev/null
+++ b/F1-nolib/Tetris/tetris.c
@@ -0,0 +1,314 @@
+/*
+ * This file is part of the TETRIS project.
+ * Copyright 2021 Edward V. Emelianov <edward.emelianoff@gmail.com>.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "adcrandom.h"
+#include "buttons.h"
+#include "screen.h"
+#include "tetris.h"
+
+#include "usb.h"
+#include "proto.h"
+
+// backround color
+#define BACKGROUND_COLOR    (COLOR_BLACK)
+#define CUP_COLOR           (COLOR_LRED)
+
+// height of cup
+#define CUPHEIGHT       (30)
+#define CUPWIDTH        (20)
+// screen coordinate of x=0 @ cup
+#define CUPX0           (1)
+// screen coordinate of y=0 @ cup (Y grows upside down)
+#define CUPY0           (0)
+// coordinates of "NEXT figure"
+#define NEXTX0          (30)
+#define NEXTY0          (4)
+#define xmax            (CUPWIDTH-1)
+#define ymax            (CUPHEIGHT-1)
+
+// min speed
+#define MAXSTEPMS       (199)
+// max speed / drop speed
+#define MINSTEPMS       (19)
+// each NXTSPEEDSCORE of score the speed will be increased
+#define NXTSPEEDSCORE   (50)
+
+extern uint32_t Tms;
+
+// get coordinates by figure member
+#define GETX(u) (((u) >> 4) - 2)
+#define GETY(u) (((u) & 0xf) - 2)
+
+typedef struct{
+    uint8_t f[4];
+    uint8_t color;
+} figure;
+
+// L: 00, 01, 02, 10 + 2 = 0x22, 0x23, 0x24, 0x32
+static const figure L = {
+    .f = {0x22, 0x23, 0x24, 0x32},
+    .color = COLOR_LBLUE
+};
+// J: 00, 01, 02, -10 + 2 = 0x22, 0x23, 0x24, 0x12
+static const figure J = {
+    .f = {0x22, 0x23, 0x24, 0x12},
+    .color = COLOR_BLUE
+};
+// O: 00, 01, 10, 11 + 2 = 0x22, 0x23, 0x32, 0x33
+static const figure O = {
+    .f = {0x22, 0x23, 0x32, 0x33},
+    .color = COLOR_YELLOW
+};
+
+// I: 0-1, 00, 01, 02 + 2 = 0x21, 0x22, 0x23, 0x24
+static const figure I = {
+    .f = {0x21, 0x22, 0x23, 0x24},
+    .color = COLOR_CYAN
+};
+
+// S: -10, 00, 01, 11 + 2 = 0x12, 0x22, 0x23, 0x33
+static const figure S = {
+    .f = {0x12, 0x22, 0x23, 0x33},
+    .color = COLOR_LGREEN
+};
+
+// Z: -11, 01, 00, 10 + 2 = 0x13, 0x23, 0x23, 0x32
+static const figure Z = {
+    .f = {0x13, 0x23, 0x23, 0x32},
+    .color = COLOR_GREEN
+};
+
+// T: -10, 01, 00, 10 + 2 = 0x12, 0x23, 0x22, 0x32
+static const figure T = {
+    .f = {0x12, 0x23, 0x22, 0x32},
+    .color = COLOR_PURPLE
+};
+
+#define FIGURESNUM  (7)
+static const figure *figures[FIGURESNUM] = {&L, &J, &O, &I, &S, &Z, &T};
+static figure curfigure, nextfigure;
+
+// current figure coordinates
+static int xf, yf;
+// next score the speed will be encreased
+static uint32_t nextSpeedScore = 0;
+
+
+// chk if figure can be put to (x,y); @return 1 if empty
+static int chkfigure(int x, int y, const figure *F){
+    if(x < 0 || x > xmax) return 0;
+    if(y < 0 || y > ymax) return 0;
+    for(int i = 0; i < 4; ++i){
+        int xn = x + GETX(F->f[i]), yn = y + GETY(F->f[i]);
+        if(yn > ymax || yn < 0) return 0;
+        if(xn < 0 || xn > xmax || yn < 0) return 0; // border
+        if(GetPix(xn ,yn) != BACKGROUND_COLOR) return 0; // occupied
+    }
+    return 1;
+}
+
+// clear figure from old location
+static void clearfigure(int x, int y){
+    USB_send("Clear @ "); USB_send(u2str(x)); USB_send(", "); USB_send(u2str(y)); USB_send("\n");
+    for(int i = 0; i < 4; ++i){
+        int xn = x + GETX(curfigure.f[i]), yn = y + GETY(curfigure.f[i]);
+        if(xn < 0 || xn > xmax || yn < 0 || yn > ymax) continue; // out of cup
+        DrawPix(xn, yn, BACKGROUND_COLOR);
+    }
+}
+
+// put figure into new location
+static void putfigure(int x, int y, figure *F){
+    USB_send("Put @ "); USB_send(u2str(x)); USB_send(", "); USB_send(u2str(y)); USB_send("\n");
+    for(int i = 0; i < 4; ++i){
+        int xn = x + GETX(F->f[i]), yn = y + GETY(F->f[i]);
+        if(xn < 0 || xn > xmax || yn < 0 || yn > ymax) continue; // out of cup
+        DrawPix(xn, yn, F->color);
+    }
+}
+
+// dir=-1 - right, =1 - left
+static void rotatefigure(int dir, figure *F){
+    figure nF = {.color = F->color};
+    for(int i = 0; i < 4; ++i){
+        int x = GETX(F->f[i]), y = GETY(F->f[i]), xn, yn;
+        if(dir > 0){ // CW
+            xn = y; yn = -x;
+            USB_send("Rotate CW\n");
+        }else if(dir < 0){ // CCW
+            xn = -y; yn = x;
+            USB_send("Rotate CCW\n");
+        }
+        nF.f[i] = ((xn + 2) << 4) | (yn + 2);
+    }
+    *F = nF;
+}
+
+// check cup for full lines & delete them; return number of deleted lines
+static int checkandroll(){
+    int upper = 0, ret = 0;
+    for(int y = 0; y < CUPHEIGHT; ++y){
+        int N = 0;
+        for(int x = 0; x < CUPWIDTH; ++x)
+            if(GetPix(x, y) != BACKGROUND_COLOR) ++N;
+        if(N == 0) upper = y;
+        else if(N == CUPWIDTH){ // full line - roll all upper
+            ++ret;
+            for(int yy = y; yy <= upper; --yy){
+                uint8_t *ptr = &screenbuf[(yy+CUPY0)*SCREEN_WIDTH + CUPX0];
+                for(int x = 0; x < CUPWIDTH; ++x, ++ptr)
+                    *ptr = ptr[-CUPWIDTH]; // copy upper row into the current
+            }
+            ++upper;
+        }
+    }
+    USB_send("Roll="); USB_send(u2str(ret)); USB_send("\n");
+    return ret;
+}
+
+// get random number of next figure
+static int getrand(){
+    static int oldnum[2] = {-1, -1};
+    int r = getRand() % FIGURESNUM;
+    if(r == oldnum[1]) r = getRand() % FIGURESNUM;
+    if(r == oldnum[0]) r = getRand() % FIGURESNUM;
+    oldnum[0] = oldnum[1];
+    oldnum[1] = r;
+    return r;
+}
+
+// return 0 if cannot move
+static int mvfig(int *x, int *y, int dx){
+    register int xx = *x, yy = *y;
+    int xnew = xx+dx, ynew = yy+1, ret = 1;
+    clearfigure(xx, yy);
+    if(chkfigure(xnew, ynew, &curfigure)){
+        xx = xnew; yy = ynew;
+        *x = xx; *y = yy;
+    }else ret = 0;
+    putfigure(xx, yy, &curfigure);
+    return ret;
+}
+
+// dir == -1 - left, 1 - right
+static void rotfig(int x, int y, int dir){
+    if(!dir) return;
+    figure newF = curfigure;
+    rotatefigure(dir, &newF);
+    clearfigure(x, y);
+    if(chkfigure(x, y, &newF)){ // can rotate - substitute old figure with new
+        curfigure = newF;
+    }
+    putfigure(x, y, &curfigure);
+}
+
+// draw current & next figures; return 0 if can't
+static int drawnext(){
+    curfigure = nextfigure;
+    clearfigure(NEXTX0, NEXTY0); // clear NEXT
+    nextfigure = *figures[getrand()];
+    putfigure(NEXTX0, NEXTY0, &nextfigure);
+    xf = xmax/2; yf = ymax/2;
+    if(!chkfigure(xf, yf, &curfigure)) return 0; // can't draw next
+    putfigure(xf, yf, &curfigure);
+    return 1;
+}
+
+void tetris_init(){
+    setBGcolor(BACKGROUND_COLOR);
+    ClearScreen();
+    ScreenON();
+    StepMS = MAXSTEPMS;
+    Tlast = Tms;
+    incSpd = StepMS;
+    score = 0;
+    nextSpeedScore = NXTSPEEDSCORE;
+    // draw cup
+    for(int y = 0; y < CUPHEIGHT; ++y){
+        DrawPix(CUPX0, CUPY0 + y, CUP_COLOR);
+        DrawPix(CUPX0 + CUPWIDTH, CUPY0 + y, CUP_COLOR);
+    }
+    for(int x = 0; x < CUPWIDTH; ++x)
+        DrawPix(CUPX0 + x, CUPY0 + CUPHEIGHT, CUP_COLOR);
+    nextfigure = *figures[getrand()];
+    drawnext();
+}
+
+// process tetris game; @return 0 if game is over
+int tetris_process(){
+    uint8_t moveX = 0, rot = 0;
+    keyevent evt;
+    static uint8_t paused = 0;
+    // change moving direction
+    if(keystate(KEY_U, &evt) && (evt == EVT_PRESS || evt == EVT_HOLD)){ // UP - pause
+        if(paused){
+            USB_send("Tetris resume\n");
+            paused = 0;
+        }else{
+            USB_send("Tetris paused\n");
+            paused = 1;
+        }
+    }
+    if(keystate(KEY_D, &evt) && evt == EVT_PRESS){ // Down - drop
+        incSpd = MINSTEPMS;
+    }
+    if(keystate(KEY_L, &evt) && evt == EVT_PRESS){ // L - left
+         moveX = -1;
+    }
+    if(keystate(KEY_R, &evt) && evt == EVT_PRESS){ // Right
+        moveX = 1;
+    }
+    if(keystate(KEY_M, &evt) && evt == EVT_PRESS){ // Menu - rotate CCW
+        rot = -1;
+    }
+    if(keystate(KEY_S, &evt) && evt == EVT_PRESS){ // Set - rotate CW
+        rot = 1;
+    }
+    clear_events();
+    if(Tms - Tlast > incSpd){
+        Tlast = Tms;
+        if(paused) return 1;
+        int xnew = xf, ynew = yf;
+        if(rot) rotfig(xf, yf, rot);
+        if(!mvfig(&xnew, &ynew, moveX) && ynew == yf){ // can't move: end of moving?
+            int s = checkandroll();
+            switch(s){ // add score
+                case 1:
+                    score += 1;
+                break;
+                case 2:
+                    score += 3;
+                break;
+                case 3:
+                    score += 7;
+                break;
+                case 4:
+                    score += 15;
+                break;
+                default:
+                break;
+            }
+            if(StepMS > MINSTEPMS && score > nextSpeedScore){ // increase speed
+                --StepMS;
+                nextSpeedScore += NXTSPEEDSCORE;
+            }
+            if(!drawnext()) return 0;
+        }
+    }
+    return 1;
+}
diff --git a/F1-nolib/Tetris/tetris.h b/F1-nolib/Tetris/tetris.h
new file mode 100644
index 0000000..ca04e1b
--- /dev/null
+++ b/F1-nolib/Tetris/tetris.h
@@ -0,0 +1,25 @@
+/*
+ * This file is part of the TETRIS project.
+ * Copyright 2021 Edward V. Emelianov <edward.emelianoff@gmail.com>.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+#pragma once
+#ifndef TETRIS_H__
+#define TETRIS_H__
+
+void tetris_init();
+int  tetris_process();
+
+#endif // TETRIS_H__