-- returns if the size/length of the list is even
evenlist :: [a] -> Bool
evenlist []            = True
evenlist [a]           = False
evenlist [a,b]         = True
evenlist [a,b,c]       = False
evenlist [a,b,c,d]     = True
evenlist [a,b,c,d,e]   = False
evenlist [a,b,c,d,e,f] = True