save project

snake.py

@@ -53,13 +53,13 @@ while True:
     else:
         y += 30
     position.append((x, y))
-    position.pop(0)
     if x==applex and y==appley:
         num1=random.randint(0,21)
         num2=random.randint(0,15)
         applex=30*num1
         appley=30*num2
-        
+    else:
+        position.pop(0)  
     # 将背景图画上去
     screen.blit(background, (0, 0))
     # 将贪吃蛇的头画上去