There are two ways to satisfy "Group the green block and the red apple": either the robot can lift the red apple and place it near the green block, or it can lift the green block and place it near the red apple. The planning system selects between these alternatives based on prior **data** about objects with the given attributes (green, red, block, and apple). The plan tree is constructed using the choice with the highest predicted success likelihood. The planning system's search will produce a series of action processes, which are interaction processes that issue motor commands and monitor their progress.