A spatial grid consisting of three mutually perpendicular fakir probes, halfway shifted with respect to each other, applied to the measurement of the surface area of a 3D object (shown on 3D reconstruction of tobacco cells here). The number of intersections (red “balls”) of the fakir probes (green “pipes”) and object walls is proportional to the object surface area. Method developed in the Department of Biomathematics. Image obtained in cooperation with Prof. Z. Opatrny, Faculty of  Science, Charles University in Prague.