rsearch( lowk, uppk, t, lev )
     typekey lowk[], uppk[];
     tree t;
     int lev;

     {int j;
     if ( t==NULL ) return;
     if ( lowk[lev] <= t->k[lev] )
          rsearch( lowk, uppk, t->left, (lev+1)%K );

     for ( j=0; j<K && lowk[j]<=t->k[j] && uppk[j]>=t->k[j]; j++ );
     if ( j==K ) found( t );

     if ( uppk[lev] > t->k[lev] )
          rsearch( lowk, uppk, t->right, (lev+1)%K );
     };