The Oxford Mathematical Institute has one just outside the entrance. We also have Penrose himself though :P
More info:
https://www.maths.ox.ac.uk/about-us/life-oxford-mathematics/... http://www.maths.ox.ac.uk/node/865
More info:
https://www.maths.ox.ac.uk/about-us/life-oxford-mathematics/... http://www.maths.ox.ac.uk/node/865
http://www.tilexdesign.com/portfolio/detail.cfm/C/328/Carlet...