iso paper sizes are delicious: sides are 1:sqrt2 or about 1:1.414

A4 is 210x297mm

A4 folded in half is 148x210 or A5.

A3 is two A4s, or 297x420

go to A0 841x1189 or one square metre.

A-1 (A Minus One) is 2 square metres.

Australia is ~A-43

The visible universe ~A-179

A proton about A139.

A Quark? A151

Presumably A232 is one dimensional though, as it's planck length on the long edge.