Ribbons of superparamagnetic colloids in magnetic field A. Darras, J. Fiscina, M. Pakpour, N. Vandewalle and G. Lumay Eur. Phys. J. E, 39 4 (2016) 47 Published online: 27 April 2016 DOI: 10.1140/epje/i2016-16047-0