CF1950B Upscaling

You are given an integer $ n $ . Output a $ 2n \times 2n $ checkerboard made of $ 2 \times 2 $ squares alternating ' $ \texttt{#} $ ' and ' $ \texttt{.} $ ', with the top-left cell being ' $ \texttt{#} $ '. The picture above shows the answers for $ n=1,2,3,4 $ .

The first line contains an integer $ t $ ( $ 1 \leq t \leq 20 $ ) — the number of test cases. The only line of each test case contains a single integer $ n $ ( $ 1 \leq n \leq 20 $ ) — it means you need to output a checkerboard of side length $ 2n $ .

For each test case, output $ 2n $ lines, each containing $ 2n $ characters without spaces — the checkerboard, as described in the statement. Do not output empty lines between test cases.