solutions

:: attr-base
value of `self.attr` as observed by base is: 
value of `base.attr` as observed by child is: 
base attribute

:: attr-base-calculated
value of `base.calculated-attr` as observed by attr-base-calculated is: 
value of `self.attr` as observed by base is: 
base attribute

:: attr-base-calculated-constant
value of `base.calculated-attr` as observed by attr-base-calculated is: 
value of `self.attr` as observed by base is: 
base attribute

:: attr-constant
value of `self.attr` as observed by base is: 
constant attribute value

:: attr-self
infinite recursion

:: attr-self-calculated
value of `self.calculated-attr` as observed by child is: 
value of `self.attr` as observed by base is: 
child attribute

:: attr-self-calculated-constant
value of `self.calculated-attr` as observed by child is: 
grandchild calculated attribute

:: attr-self-constant
value of `self.attr` as observed by base is: 
grandchild attribute

:: attr-super
value of `self.attr` as observed by base is: 
value of `super.attr` as observed by child is: 
base attribute

:: attr-super-calculated
value of `super.calculated-attr` as observed by child is: 
value of `self.attr` as observed by base is: 
child attribute

:: attr-super-calculated-constant
value of `super.calculated-attr` as observed by child is: 
value of `self.attr` as observed by base is: 
child attribute

:: attr-union
value of `self.attr` as observed by base is: 
base attribute