A data buffering device which contains an input unit adapted to sequentially receive a two-dimensional array of data structures organized by an index pair with a first index stepwise traversing first-index values in a meandering manner defined by a first and a second meandering direction. The synthesis consists of a single vessel acid catalyzed ring opening polymerization and may be employed to produce copolymers useful as hydrogel contact lens materials. The method further comprises a2) performing a decision action for each writing action in which a decision whether or not to perform the verification action for a specific written data portion is taken. Also disclosed herein is a filler material having the silicon atom of a silacyclobutane group is directly or indirectly bound thereto. Combining two HMF sensor systems creates a steerable two-dimensional magnetic field sensor. The optical waveguide with photoelectric conversion element is bendable in a region including the thin portion in such a direction that the under-cladding layer faces inward.