Every time she makes a purchase and there are cents involved she holds up the cashier’s line by unzipping the change pocket in her wallet and carefully fingering through the coins, yielding a coppery odor, pushing aside the bicentennial quarter and the dark wheat penny to place exact and shiny change in the clerk’s open palm. In this way she contributes to her day’s perfect balance (defined not as what remains after other parts are subtracted but as the most stable of states brought on by equal and opposing forces), although she sees the clerk as opposing but not equal.