adds flowchart

learning_python3.md

@@ -65,6 +65,22 @@ TODO animated overview of the shell and the world of OOP
 
 # Installing pycharm
 
+Depending on the platform you use, you can install Pycharm in multiple ways.
+The computers in the classroom come with Pycharm installed but if you want to continue working from home you can follow the instructions [here](https://www.jetbrains.com/pycharm/download/#section=windows).
+
+If you run Windows at home you will probably need to install python as well.
+Download the latest version from [here](https://www.python.org/downloads/).
+On Linux and Mac OSX there will probably be some version of python installed.
+From a terminal you can check the version that's installed by executing the following commmands.
+
+```bash
+waldek@metal:~$ python3 --version
+Python 3.9.2
+waldek@metal:~$ 
+```
+
+## Virtual environments
+
 TODO
 
 # Your first project
@@ -209,7 +225,7 @@ But how can we **get** some information from the user?
 This is done with the built-in `input` function.
 If we open up a python shell we can observe it's behaviour.
 
-```python3
+```python
 >>> input()
 hello world
 'hello world'
@@ -436,7 +452,7 @@ You should do this in a **new** python file.
 I suggest you call it `c_to_f.py` or something that makes sense to you.
 The result of this program *could* be as follows.
 
-```bash
+```
 ➜  ~ git:(master) ✗ python3 ex_celcius_to_fahrenheit.py
 What's the temperature?30
 30°C equals 86.0°F
@@ -1184,19 +1200,17 @@ while counter <= 10:
 
 print("after the loop, counter: {}".format(counter))
 ```
-<details>
-  <summary>Another example</summary>
+
+Or with only variables and a more verbose way of incrementing the numbers.
 
 ```python3
-FirstValue = 2
-SecondValue = 0
-while FirstValue>SecondValue:
-    print("The second value is bigger")
-    SecondValue = SecondValue + 1
+first_value = 20
+second_value = 0
+while first_value > second_value:
+    print("second value {} is smaller than {}".format(second_value, first_value))
+    second_value = second_value + 1
 ```
 
-</details>
-
 Two *extra* things might look new to you here.
 First the `import time` and `time.sleep(1)`, can you tell me what it does?
 Next the `counter += 1` which is called [incrementing](https://stackoverflow.com/questions/1485841/behaviour-of-increment-and-decrement-operators-in-python).
@@ -1247,12 +1261,17 @@ print("after the loop, counter: {}".format(counter))
 Infinite loops are a cornerstone of modern programming.
 While they might look scary, don't overthink it, you'll get used to them very quickly.
 
+Logical procedures can be drawn out with flow charts.
+An example can be seen in the image below.
+
+[flowchart while loop](./assets/flowchart_while_01.png)
+
 ⛑ **When testing out an infinite loop it's sometimes handy to insert a `time.sleep` in it to slow down the execution a bit so you can wrap your head around what's happening.**
 
 🏃 Try it
 ---
 
-Go back to the Celsius to Farenheit converter and add a while loop to ensure the user puts in only numbers.
+Go back to the Celsius to Fahrenheit converter and add a while loop to ensure the user puts in only numbers.
 
 
 # Coding challenge - Guess the number