my and-or-tree
consists of and-nodes and or-nodes
because there are more possibilities
(to complete a goal)
and-nodes split up a main goal into many partial goals
and all partial goals simultaneously fulfilled
fulfill the main goal
Two roads diverged, in a yellow wood,
You clicked the link as you knew you should
And somewhere deep beneath the ground
Some dwarves searched for what should be found
But being dwarves, your search got old,
And so they turned their minds to gold
With more searching, you might give them more urging,
But here's a page on metalurging: