-- returns a list with all elements from odd positions from the input list
oddpos :: [a] -> [a]
oddpos [] = []
oddpos [a] = [a]
oddpos [a,b] = [a]
oddpos [a,b,c] = [a,c]
oddpos [a,b,c,d] = [a,c]
oddpos [a,b,c,d,e] = [a,c,e]