Büchi Dreiding stereomodel molecular model kit box 1960 Switzerland

Mr. Dreiding was a Swiss professor in the Chemistry and invented this molecular Stereo-model kit to build models of chemicals. It is a skeletal model consisting of stainless steel tubes and rods, where the atoms were not represented by a ball but by the point of color painted intersection of the steel tubes. The model focused on the geometry of the bonds between atoms rather than the atoms themselves, where the degrees / radius between the atoms and the lengths of the bonds made it possible to do calculations and build bonds in 3 dimensional models. There were basic kits as well as extra sets to make specific model. I believe the 3 cards included point towards these extras. The whole kit contains 83 pieces in total. The box is an early example with the Büchi company name on it. Later boxes would also have the Dreiding name on them since this model kit got well known under the good professors own name. This set was produced somewhere in the 1960’s in Switzerland and is in very good and usable condition.  The box  shows some signs of age and use and measures ca 20 cm or 8 inches wide. More information on these models can be find here: https://gfp.people.uic.edu/dreiding/dreidingexchange.htm