[Haskell-beginners] A simple function

Hallo liebe Leute. Hola gente. I'm starting with Haskell and i have some problems: *intercalate :: [t] -> [t] -> [t]* *intercalate [a,b] [c,d] = [a,c,b,d]* *intercalate (_) (_) = error "JOJO u cant do this"* Are there any form to restrict the parmaters that only allow to call the function *intercalate* with two arrays of two elements, in compilation time? Cause i cant write* intercalete :: [t,t] -> [t,t]->[t,t,t,t]*. Sorry for my bad english. I'm Argentinean. Thanks!