Instrucciones de SQL: dibujar patrones escarchados en SQL

 WITH RECURSIVE T AS ( SELECT 0 x , 0 y , '{"{0,0}"}'::text[] c --     , 0 i UNION ALL ( WITH Z AS ( SELECT dn.x , dn.y , Tc , Ti FROM T --      , LATERAL( SELECT ((random() * 2 - 1) * 100)::integer x , ((random() * 2 - 1) * 100)::integer y ) p --         , LATERAL( SELECT * FROM ( SELECT (unnest::text[])[1]::integer x , (unnest::text[])[2]::integer y FROM unnest(Tc::text[]) ) T ORDER BY sqrt((x - px) ^ 2 + (y - py) ^ 2) LIMIT 1 ) n --  8         , LATERAL ( SELECT nx + dx x , ny + dy y FROM generate_series(-1, 1) dx , generate_series(-1, 1) dy WHERE (dx, dy) <> (0, 0) ORDER BY CASE WHEN (px, py) = (nx, ny) THEN 0 ELSE abs(acos(((px - nx) * dx + (py - ny) * dy) / sqrt((px - nx) ^ 2 + (py - ny) ^ 2) / sqrt(dx ^ 2 + dy ^ 2))) END LIMIT 1 ) dn ) SELECT Zx , Zy , Zc || ARRAY[Zx, Zy]::text , Zi + 1 FROM Z WHERE Zi < (1 << 10) ) ) --         , map AS ( SELECT gx x , gy y , ( SELECT sqrt((gx - Tx) ^ 2 + (gy - Ty) ^ 2) v FROM T ORDER BY v LIMIT 1 ) v FROM generate_series(-70, 70) gx , generate_series(-35, 35) gy ) --    , gr AS ( SELECT regexp_split_to_array('#****++++----.... ', '') s ) --   SELECT string_agg( coalesce(s[(v * (array_length(s, 1) - 1))::integer + 1], ' ') , ' ' ORDER BY x) frozen FROM ( SELECT x , y , v::double precision / max(v) OVER() v --      FROM map ) T , gr GROUP BY y ORDER BY y;