Turing Machines

If someone could answer this please I will be extremely grateful, thank you.

6. Draw or describe the following Touring Machines (TMs) as required: a. [5 marks] Draw a TM with 2 = {a, b} that for any input changes each a to b and each b to a. Briefly describe in your own words how it works. b. [5 marks] Describe a TM that enumerates all even-length strings for a unary alphabet