How do you store an abstract idea (like "inflation" or a number) that has no obvious picture?

Swap it for a concrete stand-in — a symbol, a pun, or a coded image — then place that.

Abstractions won't hang on a locus, so convert first:

• Symbol / association: inflation → a balloon swelling until it bursts; justice → a pair of scales.
• Pun / sound-alike: Argentina → a silver ("argent") tin; nitrogen → a knight ("night").
• Coded image: a number → its Major-System word; a person → a caricature.

Once it's a concrete, picturable thing, the normal placing rules apply.