This is done by introducing two opportunely designed masks (sometimes referred to as coded-aperture masks), one immediately before the sample, and one in contact with the detector (see figure).
In that intimate association between the two men who had met so opportunely on the "perron des varits", it was often asked who was the leading partner.
The realisation of massive consolidated ground elements of various shapes and sizes (buttresses and spurs) within the mass to be stabilised, is achieved by acting opportunely on the injection parameters.
