AJ on Instagram: "A4 paper isn’t random — it’s mathematically engineered. The entire A‑series (A0, A1, A2… A4) is based on one genius idea: a rectangle where the ratio of the sides stays the same when you cut it in half. That magic ratio? \(\sqrt{2}\) : 1 A0 is the starting point — exactly 1 square metre in area. Cut it in half → A1 Cut that in half → A2 Keep going → A4 Because the proportions never change, A‑size paper scales perfectly for printing, copying, and folding. No stretching. No disto