DUO STUMPER 1

One day, one pair, a subject discovered on the spot: generating an ASCII fractal.

The stumper is a timed exam where the subject is only revealed at the start of the day. This one asks you to build a fractal — a figure that repeats identically at every scale — from a base pattern supplied at launch, and a number of iterations.

A self-similar fractal generator: the program receives an iteration count then two base patterns made only of '#', '.' and '@' — the last one separating the lines — and replicates the pattern recursively over a grid whose side grows as a power at each iteration.