The office of Professor Robinson is quite simply decorated, as he's never been one to spend outlandish funds on fancy decor. That and your professor recently moved here from another continent, so furnishing has been a difficult and slow process. But within the office, you'll see a large wooden desk, with a comfortable executive style ergonomic office chair. On the other side will be two mismatched looking armchairs. There's also a bookshelf off to the one side that provides resources for Arithmancy as well as the French and Latin languages. There's a two framed photographs on one the shelves as well, one of his daughter and the other from his wedding day
(even though he's separated, it was a spectacular day and she is the mother of his child and he definitely still has a strong connection to her)
There's also a wall hanging of an Australian flag, hand-knit that is behind his chair, a subtle tribute to his home country.
Whether you've come for extra help, or just to simply 'get-to-know' your new professor, if you are nice enough, he might just offer you a Cadbury chocolate.