two different objects, but somehow the values are shared between them

[nilamo]

Im used to C (C# and C++)

Ok, so what you're doing, in terms of those other languages, is having a static variable position that's unbound from any instance. In python, they're called class attributes/methods instead of static, but it's essentially the same thing. In order to have instance variables, they'd need to be defined in the __init__ method, not outside of there.

Here's some example code to try to show the difference:

>>> class Spam:
...   # class attribute, shared by all instances
...   things = []
...   def add(self, thing):
...     self.things.append(thing)
...     return self.things
...
>>> eggs = Spam()
>>> eggs.add("first")
['first']
>>> ham = Spam()
>>> ham.add("second")
['first', 'second']
>>> Spam.things
['first', 'second']
>>>
>>> class Bike:
...   def __init__(self):
...     self.things = []
...   def add(self, thing):
...     self.things.append(thing)
...     return self.things
...
>>> two_wheels = Bike()
>>> two_wheels.add("first")
['first']
>>> four_wheels = Bike()
>>> four_wheels.add("second")
['second']
>>> Bike.things
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
AttributeError: type object 'Bike' has no attribute 'things'