save project

snake.py

@@ -53,10 +53,12 @@ while True:
     else:
         y += 30
     position.append((x, y))
-    position.pop(0)
     if x ==xa and y == ya:
-        xa = random.randint(0,660)
-        ya = random.randint(0,480)
+        n1 = random.randint(0,21)
+        n2 = random.randint(0,15)
+        xa = n1 * 30
+        ya = n2 * 30
+        position.pop(0)
     # 将背景图画上去
     screen.blit(background, (0, 0))
     # 将贪吃蛇的头画上去