Initial data commit

Task/Fractal-tree/PL-pgSQL/fractal-tree-2.sql

@@ -0,0 +1,14 @@
+WITH RECURSIVE noeuds(azimuth, x0, y0, x, y, len, n) AS (
+    VALUES (pi()/2, 0::real, 0::real, 0::real, 10::real, 10::real, 9::int)
+  UNION all
+    select azimuth+a, x, y, (x+cos(azimuth+a)*len)::real, (y+sin(azimuth+a)*len)::real, (len/2)::real, n-1
+    FROM noeuds
+    cross join (select (-pi()/7)::real a union select (pi()/7)::real a2) a
+    WHERE n > 0
+)
+, branche as (
+    select '('||x0||' '||y0||','||x||' '||y||')' b
+    from noeuds
+)
+select ST_GeomFromEWKT('SRID=4326;MULTILINESTRING('||string_agg(b, ',')||')') tree
+from branche