Using variables across modules

[Aaron Scott]

I'm having some trouble understanding how Python handles variables
across multiple modules. I've dug through the documentation, but I
still find myself at a loss.

When you import a module, are you creating an instance of the
variables within? For instance, if I have one file, "variables.py",
which contains "myvar = 0", and I import it into both "foo.py" and
"bar.py" with the line "from variables import *", and then set myvar
in "foo.py" and "bar.py" to different values, will each file have a
different value for myvar? If so, how can I ensure that a change to
myvar in "bar.py" is reflected by "foo.py"? Or am I completely off
base?