  Slime mould Physarum polycephalum builds up sophisticated networks to
transport nutrients between distant part of its extended body. The slime
mould's protoplasmic network is optimised for maximum coverage of nutrients yet
minimum energy spent on transportation of the intra-cellular material. In
laboratory experiments with P. polycephalum we represent Canadian major urban
areas with rolled oats and inoculated slime mould in the Toronto area. The
plasmodium spans the urban areas with its network of protoplasmic tubes. We
uncover similarities and differences between the protoplasmic network and the
Canadian national highway network, analyse the networks in terms of proximity
graphs and evaluate slime mould's network response to contamination.
