Recreated Snake in Rust

This is my first ever program in Rust, I’ve made it using only the book, the reference, and any documentation about the crates/functions i was using on the official rust lang website.

I have the feeling this could be cleaned up a lot, looking for suggestions.

extern crate rand; extern crate device_query;  use std::{vec, thread::sleep, time::Duration}; use rand::*; use device_query::{DeviceQuery, DeviceState, Keycode};  fn main(){     let device_state = DeviceState::new();     let mut rows = [['⬛'; 11]; 11];     let mut score: i32 = 0;     let mut direction: u8 = 0; // = Up, 1 = Left, 2 = Down, 3= Right     let mut positions:Vec<(usize, usize)>  = vec![(5,5)]; //every square taken by our slithery friend     let mut close_game: bool = false;     rows[5][5] = '🟩';     rows[3][5] = '🍎';     while !close_game {         print!("\x1B[2J\x1B[1;1H");         direction = input_direction(direction, &device_state);         close_game = game_tick(&mut rows, &mut positions, direction, &mut score);         draw_game(&rows, &score);         sleep(Duration::from_millis(300));     }     println!("Game over! Final Score: {}", score); }   fn draw_game(a: &[[char;11];11], score: &i32){     println!("");     println!("  Score:{:02} teo.snake", &score);     for i in 1..10 {         print!("  ");         for j in 1..10 {             print!("{}", a[i][j]);         }         println!("");     } }  fn game_tick(a: &mut[[char;11];11], vec: &mut Vec<(usize, usize)>, d: u8, s: &mut i32)-> bool {     let mut game_over: bool = false;     let newpos: (usize, usize)= newposition(d, vec[0], &mut game_over);     if game_over == true {         return game_over     }      for i in 0..vec.len() {         if newpos == vec[i] {             game_over = true;             return game_over         }     }     vec.insert(0, newpos);      let mut next_fruitx:usize;     let mut next_fruity:usize;     let mut checkpass: bool;      'looptillvalid: loop {         checkpass = true;         next_fruitx = rand::thread_rng().gen_range(1..10);         next_fruity = rand::thread_rng().gen_range(1..10);         for i in 0..vec.len() {             if (next_fruitx, next_fruity) == vec[i] {                 checkpass = false;                 break;             }         }         if checkpass == true {                 break 'looptillvalid;         }     }     let lastpos: (usize, usize) = vec.pop().unwrap();     a[lastpos.0][lastpos.1] = '⬛';      match a[newpos.0][newpos.1] {         '🍎' => { vec.push(lastpos);             a[newpos.0][newpos.1] = '🟩';              a[lastpos.0][lastpos.1] = '🟩';             *s += 1;              game_over = false;             a[next_fruitx][next_fruity] = '🍎';         }          _  => { a[newpos.0][newpos.1] = '🟩';             game_over = false}     }      game_over }  fn newposition(d: u8, first: (usize, usize), go: &mut bool) -> (usize, usize){     let mut ret: (usize, usize) = (0,0);     match d {         0 => { ret.0 = first.0 - 1; ret.1 = first.1}         1 => { ret.0 = first.0; ret.1 = first.1 - 1}         2 => { ret.0 = first.0 + 1; ret.1 = first.1}         3 => { ret.0 = first.0; ret.1 = first.1 + 1}         _ => {println!("Invalid Direction")}     }      if ret.0 < 1 || ret.0 > 9 || ret.1 < 1 || ret.1 > 9 {         *go = true;     }      ret }  fn input_direction(d: u8, d_state: &DeviceState) -> u8{      let mut dir: u8 = d;          let keys: Vec<Keycode> = d_state.get_keys();          if keys.len() != 0 {             match keys[0] {                                  Keycode::Up => {dir = 0}                 Keycode::Left => {dir = 1}                 Keycode::Down => {dir = 2}                 Keycode::Right => {dir = 3}                 _ => ()             }         }     dir }