Once, two rats were talking. br 'Try this, ' said the first. br 'It is of xanthous essence with bewildering taste br Humans call it swiss cheese.' br 'That's fascinating, ' said the second rat. br 'I've got a florid essence of my own called, br sharp cheddar.' br br They decided to trade, br But each was worried losing his favorite flavor. br Each surreptitiously took a mouthful of br What they have in hand, first. br Then each blurted the same. br 'There's no difference.' br They agreed, it wasn't br A fair trial.