Arrow keys to steer, Back to exit. Wrapping edges, speed increases, extra food every 5 points.

# Snake - NumWorks
# Created by Alvar Laigna - https://alvarlaigna.com
from random import randint
from ion import keydown
from ion import KEY_BACK,KEY_UP,KEY_DOWN
from ion import KEY_LEFT,KEY_RIGHT
from kandinsky import fill_rect,draw_string
from time import sleep

W,H = 32,22
BG = (255,255,255)
SN = (0,200,0)
HD = (0,0,200)
FD = (255,0,0)

def dr(c,r,col):
  fill_rect(c*10,r*10,10,10,col)

def food(s,fl):
  while True:
    f = (randint(0,W-1),randint(0,H-1))
    if f not in s and f not in fl:
      return f

def run():
  s = [(0,0),(1,0),(2,0)]
  h = (2,0)
  d = "R"
  fl = {food(s,set())}
  fill_rect(0,0,320,222,BG)
  for c,r in s[:-1]:
    dr(c,r,SN)
  dr(h[0],h[1],HD)
  for f in fl:
    dr(f[0],f[1],FD)
  while True:
    if keydown(KEY_BACK): break
    if keydown(KEY_UP) and d!="D": d="U"
    if keydown(KEY_RIGHT) and d!="L": d="R"
    if keydown(KEY_DOWN) and d!="U": d="D"
    if keydown(KEY_LEFT) and d!="R": d="L"
    if d=="U": h=(h[0],(h[1]-1)%H)
    elif d=="R": h=((h[0]+1)%W,h[1])
    elif d=="D": h=(h[0],(h[1]+1)%H)
    elif d=="L": h=((h[0]-1)%W,h[1])
    if h in s: break
    s.append(h)
    dr(h[0],h[1],HD)
    if h in fl:
      fl.discard(h)
      fl.add(food(s,fl))
      if len(s)%5==0:
        fl.add(food(s,fl))
    else:
      t = s.pop(0)
      dr(t[0],t[1],BG)
    for f in fl:
      dr(f[0],f[1],FD)
    p = s[-2]
    dr(p[0],p[1],SN)
    sleep(max(0.05,0.25/len(s)**0.5))
  fill_rect(85,80,150,55,(220,220,220))
  draw_string("GAME OVER",100,85,FD,
    (220,220,220))
  draw_string("Score: "+str(len(s)),
    105,108,(0,0,0),(220,220,220))
  while not keydown(KEY_BACK):
    sleep(0.1)

run()