If you don't have the best understanding of Afrikaans, I'll try my best to explain the concept as simple as possible. The human-truth behind the overall concept is that each person has a unique way of dipping their rusks. This also extends to wordplay on the Afrikaans language
Our main idea derives from the Afrikaans language, keeping in mind the human truth that is... Every individual has a different way of dipping their rusk. Some use a spoon, some do it quick, some prefer to keep the rusk in soaking in the coffee or tea for a long while. This human truth combined with some clever wordplay gave us our end-result. Translating from Afrikaans, Ouma and gran. The idea shows exactly that, different ways of dipping your gran(Ouma).