The subject disclosure relates to generating three-dimensional fa\xe7ade models from images. A difference computing arrangement computes a difference between a predetermined reference value and an initial measured value of the measurement signal of the raindrop sensor. The first contact layer is composed of GaAs or InGaAs doped with n type impurities with a high electron mobility. Each set of printed variable data fields includes at least a first data field printed with a numeric code, the numeric code of each variable data field set being different from that of each other set printed on the first side of the core. This system takes advantage of the reversible divalent cation switch that this capsid employs to assemble and disassemble.