# there is a 0.6 chance that a souffle rises is beaten well and it is quie\
t
        $p->a( souffle_rises(0.6) => qw(beaten_well quiet_while_cooking) ) ;

     # there is a 0.1 chance that it will rise based on luck
        $p->a( souffle_rise(0.1 ) => 'have_luck');

     # there is thus 0.3 chance that it will NOT rise

        $p->a( beaten_well(0.4)   => 'use_whisk');
        $p->a( beaten_well(0.6)   => 'use_mixer');

        $p->a( quiet_while_cooking(0.8) => 'kids_outside');
        $p->a( have_luck(0.3) => 'knock_on_wood');

     # tell me what the chances are of this souffle rising if the kids are
     # outside and I use whisk...
        $p->apl( qw(use_whisk kids_outside) );

     $p->top_down('souffle_rise')