2d versus 1d Turing machine apparently. Here is the paper claiming universality:...

		da-bacon on Sept 4, 2014 \| parent \| context \| favorite \| on: Langton's ant 2d versus 1d Turing machine apparently. Here is the paper claiming universality: http://www.dim.uchile.cl/~anmoreir/oficial/langton_dam.pdf