newbie syntax question

Hi, I am extremely new to Haskell. This will be my first question, so go easy. I have just read Chapter 1 on Simon Thompson's book. for example a function declaration is given as follows scale : : Picture -> Int -> Picture If the first two types are input variables why does the syntax require me to use arrows twice? I mean isn't the following syntax more readable (hypothetically)? scale : : Picture , Int -> Picture Is there a specific reason not to be able to distinguish the input parameters from the output parameter? Thanks