[Haskell-beginners] problem exercise 3 page 60 Programming in Haskell

Hello, I don't see the answer here. If I brake down the problem. We have this : [(x,y) | x <- [1..3], y <- [4,5,6]] I have to use one generator with two nested list compreshession and make use of concat. So the x generator is [x | x <- [1..3]] and the Y genarator is [y| y <- [4..6]] So if I put it together it uses the numbers [1..6] so I could do something like this in pseudo code as guard. If generator smaller or equal 3 then its x else it's a y. But if I do concat [x,y] then I get [1..6] and that not good. If I use zip [x,y] then I get [ (1,4) (2,5) (3,6)] which is also not good but better. So im stuck now and im puzzeling the whole afternoon about this ? Anyone who can give me a hint ? Roelof