You can often tell someone's age by whether or not they know analogies in this format. It used to be a staple of standardized testing on logical deduction.

A : B :: C : D

Is read as

A is to B as C is to D. The reader is meant to understand the relationship between A and B and how it's similar to the relationship between C and D.

An easy one might be,

basketball : hoop :: hockey puck : net

But they can get quite challenging. And with multiple choice answers present in standardized testing, you often have to understand the complex relationships between many abstract concepts, and evaluate that the abstractions are of a similar type or degree.

They're actually kind of fun.

Here's an example taken from [1] (the source also has excellent discussion as to why they were removed) :

PALTRY : SIGNIFICANCE ::

  A. redundant : discussion
  B. austere : landscape
  C. opulent : wealth
  D. oblique : familiarity
  E. banal : originality

Pick the correct answer A-E.

[1] https://blog.prepscholar.com/sat-analogies-and-comparisons-w...