Blue bilby refers to the small class of Turing machines up to 6 rules, i.e. machines with 2 states and 2 symbols, 3 states and 2 symbols or 2 states and 3 symbols. 3 states and 2 symbols busy beaver is equal to 6. The name was given by James Harland as part of his Zany Zoo project.
- James Harland (2016) Busy beaver machines and the observant otter heuristic (or how to tame dreadful dragons) Theoretical Computer Science 646, 20: 61-85. (Preprint at arxiv)
- James Harland at RMIT University, Australia
- James Harland. The Busy Beaver, the Placid Platypus and other Crazy Creatures