Best test for transitivity using Haskell's Quickcheck

Of the three tests below which is the best test for transitivity. This follows from my previous question. The usual logical rule of transitivity (R(a,b) and R(b,c)) => R(a,c) does not seem apply in this case.Hence, I think that prop_trans3 would be not be a good test, because each of the three terms represents a different stack. But which of prop_trans1 and prop_trans2 are best suited to testing transitivity?

import Test.QuickCheck
data Block = Block Int deriving (Show,Eq)
-- MoveOnto(bl,b2,s) is read as b2 is moved into and onto bl on stack or table.
data Stack = EmptyTable  |  MoveOnto Block Block Stack deriving  (Show,Eq) 
isOn :: Block -> Block -> Stack -> Bool
isOn b1 b2 (MoveOnto b3 b4 s) |  ((b1 == b3) && (b4 == b2)) || (isOn b4 b2 s)   =  True
isOn _ _ _  = False

instance Arbitrary (Block) where
  arbitrary = fmap Block arbitrary

instance Arbitrary (Stack) where
  arbitrary = oneof [return EmptyTable, MoveOnto <$> arbitrary <*> arbitrary <*> arbitrary]

prop_trans1 b1 b2 s      =  isOn b1 b2 (MoveOnto b1 b2 s)
prop_trans2 b1 b2 b3 s   =  isOn b3 b1 (MoveOnto b3 b2 (MoveOnto b2 b1 s))
prop_trans3 b1 b2 b3 s   =  ((isOn b2 b1 (MoveOnto b2 b1 s)) && (isOn b3 b2 (MoveOnto b3 b2 s))) <=  (isOn b3 b1 (MoveOnto b3 b1 s))