This is the type of design idea that requires an open-mind and a load of skill. The ‘Age of the World’ project by Mathieu Lehanneur looks like it could’ve been pretty time consuming.
Age of the World is a collection of jars that are country-specific and correspond to the age of the populations. Notice the awkward rings that have no rhyme or reason - well, they do have rhyme and reason.
Each ring represents an age and the larger the ring is, the higher the population of that age in that country (still following). No two countries are the same which means no two jars are the same.
It’s rather ingenious, to say the least.