--Modified the between function to use the average distance between the robot and the two obstacles as a divisor to get everything in the 1/m units.
It didn't seem to work too well--for the sample runs that were actually between runs, got scores for between that were worse than left-of or right-of.
Need to think some more on how to do this better.
Could also use the ratio of the two distances as a unit-less multiplier/divisor, or could take the ratio of each robot-obstacle distance to the obstacle-obstacle distance.
Also thinking about somehow using the third leg of the right triangle formed with the robot-object line, object-object line, and a line from the robot perpendicular to the object-object line.
--With original lexicon, there had been 12 sentences produced (2 of them meaningless).
Expanded the list of objects from (the-table the-chair) to (the-table the-chair the-box the-ball the-bucket the-cone) to get 60 sentences (6 meaningless).
Will need to collect these obstacles for next data-gathering session--can define them with dummy locations for now.
Expanded the list of one-object prepositions from (left-of right-of behind in-front-of) to (left-of right-of behind in-front-of around towards away-from past) to bring the sentence count to 84 (still 6 meaningless sentences).
I haven't been able to think of any additional two-object prepositions.
I still need to implement longer sentences, and probably a way to join them with temporal conjunctions like (first second ... finally stopped(??) then next), etc.