From 3567c11ca6b56136c2103042026b2c856ae23c52 Mon Sep 17 00:00:00 2001
From: ennucore <ennucore@gmail.com>
Date: Mon, 20 Sep 2021 10:53:21 +0300
Subject: [PATCH] sign

---
 README.md              |  2 ++
 turtle_2/turtle_gas.py | 19 ++++++++++++++-----
 2 files changed, 16 insertions(+), 5 deletions(-)

diff --git a/README.md b/README.md
index 9a29b03..786f71a 100644
--- a/README.md
+++ b/README.md
@@ -1,5 +1,7 @@
 # Лабораторные работы для "Практики программирования на питоне"
 
+**Чижов Лев**
+
 [1. Построение графиков](http://cs.mipt.ru/python/lessons/lab1.html) - в папке `ipynb`
 
 [2. Исполнитель "Черепаха" (ч.1)](http://cs.mipt.ru/python/lessons/lab2.html) - в папке `turtle`
diff --git a/turtle_2/turtle_gas.py b/turtle_2/turtle_gas.py
index 3032689..aa0a14e 100644
--- a/turtle_2/turtle_gas.py
+++ b/turtle_2/turtle_gas.py
@@ -5,6 +5,7 @@ import math
 
 number_of_turtles = 20
 steps_of_time_number = 300
+turtle.screensize(100, 150)
 
 
 pool = [turtle.Turtle(shape='turtle') for i in range(number_of_turtles)]
@@ -13,23 +14,31 @@ for unit in pool:
     unit.speed(350)
     unit.goto(randint(-200, 200), randint(-150, 150))
     unit.left(randint(-180, 180))
+    unit.rev_x = False
+    unit.rev_y = False
 
 
 for i in range(steps_of_time_number):
     for unit in pool:
-        x, y = unit.xcor() + turtle.screensize()[0] / 2, unit.ycor() + turtle.screensize()[1] / 2
-        if x <= 0 or x >= turtle.screensize()[0]:
+        x, y = unit.xcor(), unit.ycor()
+        if abs(x) >= turtle.screensize()[0] and not unit.rev_x:
             unit.seth(90 - unit.heading())
-        if y <= 0 or y >= turtle.screensize()[1]:
+            unit.rev_x = True
+        elif not abs(x) >= turtle.screensize()[0]:
+            unit.rev_x = False
+        if abs(y) >= turtle.screensize()[1] and not unit.rev_y:
             unit.seth(-unit.heading())
+            unit.rev_y = True
+        elif abs(y) < turtle.screensize()[1]:
+            unit.rev_y = False
         unit.forward(7)
         for another_unit in pool:
             if another_unit == unit:
                 continue
             if math.hypot(another_unit.xcor() - unit.xcor(), another_unit.ycor() - unit.ycor()) < 6:
                 angle = randint(-180, 180)
-                unit.left(angle)
-                another_unit.right(angle)
+                unit.seth(angle)
+                another_unit.seth(-angle)
                 unit.forward(2)
                 another_unit.forward(2)