The value of groups_tree_var = 5000.
This comes from host, not the parents or grandparents.

The value of the grandparent variable grandparent_var is
not overridden and is = 2000

The value of the parent variable is not overridden and
is = 6000

The variable 'overridden_in_parent' is set in the parent
and grandparent, so the parent wins.  It's value is = 1000.

The values of 'uno', 'dos', and 'tres' are set in group_vars/all but 'tres' is
set to the value of 'three' in group_vars/local, which should override it.

uno = 1
dos = 2
tres = three

The values of 'a', 'b', 'c', and 'd' are set in host_vars/local and should not
be clobbered by values that are also set in group_vars.

a = 1
b = 2
c = 3
d = 4

The value of 'badwolf' is set via the include_vars plugin.

badwolf = badwolf

The value of 'winter' is set via the main.yml in the role.   

winter = coming

Here's an arbitrary variable set as vars_files in the playbook.

vars_file_var = 321

And vars.

vars = 123

Variables about other hosts can be looked up via hostvars.  This includes
facts but here we'll just access a variable defined in the groups.

999

Ansible has pretty basic precedence rules for variable overriding. We already have
some tests above about group order.  Here are a few more.

   * -e variables always win
   * then comes "most everything else"
   * then comes variables defined in inventory
   * then "role defaults", which are the most "defaulty" and lose in priority to everything.

Given the above rules, here's a test that a -e variable overrides inventory, 
and also defaults, and role vars.

etest = from -e

Now a test to make sure role variables can override inventory variables.

role_var_beats_inventory = chevron 5 encoded

Role variables should also beat defaults.

role_var_beats_default = chevron 6 encoded

But defaults are lower priority than inventory, so inventory should win.

inventory_beats_default = narf

That's the end of the precedence tests for now, but more are welcome.