( --------------------- version #1 --------------------- )

  [  not swap not 1 << |
     ]'[ swap peek do ]              is if2.1  ( b b --> )

  [ if2.1
      [ [ say "true and true"   ]
        [ say "true and false"  ]
        [ say "false and true"  ]
        [ say "false and false" ] ]
    cr ]                             is task.1 ( b b --> )

( --------------------- version #2 --------------------- )

   [ not swap not 1 << |
         dup 0 > iff ]else[ ]else[
     1 - dup 0 > iff ]else[ ]else[
     1 -     0 > iff ]else[ ]else[ ] is if2.2  ( b b --> )

   [ if2.2 [ say "true and true"   ]
      else [ say "true and false"  ]
      else [ say "false and true"  ]
      else [ say "false and false" ]
    cr ]                             is task.2 ( b b --> )

( ------------------------ demo ------------------------ )

true  true  task.1
true  false task.1
false true  task.1
false false task.1
cr
true  true  task.2
true  false task.2
false true  task.2
false false task.2