a car pulled up behind them and honked , so colin returned to driving , and by the time they were in the cavernous parking lot of the nursing home , they had settled on five variables : age ( a ) 61 popularity differential ( c ) 62 attractiveness differential ( h ) 64 dumper/dumpee differential ( d ) 63 introvert / extrovert differential ( p ) 64 they sat in the car together with the windows down , the air warm and sticky but not stifling .