Various techniques are provided for identifying a position uncertainty of a mobile device, such as, based, at least in part, on a measure of potential hindrance of an estimated trajectory. These are joined with removable snap-in pins, so the rack can be quickly assembled and taken down, and stuffed compactly into a bag for travel. Each drive surface is inclined relative to a plane containing the axis and bisecting each of the side edges. Thanks to the hole, when the stamp is removed from the unhardened concrete, the hole functions as a pressure-relief or pressure-equalizing valve eliminating undesirable distortion of the unhardened concrete and ensuring formation of desired dome-shaped concrete projections. Subsequently, the glass containers are rapidly thermally strengthened in a cooling station in which the outer and inner surfaces including all areas of the glass containers are simultaneously cooled to a temperature below the Strain Point of the glass used in the glass containers, with the cooling tube nozzles being used to cool the inner surfaces of the glass containers. The viscosity regulator is adapted to controllably vary the viscosity of the magnetorheological fluid, altering the pumping restriction against the fluid pump, resulting in variable resistance to pump shaft rotation relative to the pump housing.