Paola Flocchini Giuseppe Prencipe Nicola Santoro Peter Widmayer Arbitrary pattern formation by asynchronous, anonymous, oblivious robots. 412-447 2008 407 Theor. Comput. Sci. 1-3 http://dx.doi.org/10.1016/j.tcs.2008.07.026 db/journals/tcs/tcs407.html#FlocchiniPSW08