What is the origin of the idiom "get one's head round something" and when to use it?

The idiom "get one's head round something" means to understand or comprehend something that may be complex, difficult, or challenging to grasp initially. It implies the process of mentally processing and assimilating information or ideas until they become clear and understandable. It is commonly used in academic settings, such as when studying complex subjects or trying to comprehend intricate theories.