added notes

Python/Tree fractal.py

@@ -0,0 +1,27 @@
+import turtle
+MINIMUM_BRANCH_LENGTH = 5
+def build_tree(t, branch_length, shorten_by, angle, c):
+  if branch_length > MINIMUM_BRANCH_LENGTH:
+    t.pendown()
+    t.color(c)
+    t.forward(branch_length)
+    
+    new_length = branch_length - shorten_by
+    t.left(angle)
+    build_tree(t, new_length, shorten_by, angle, "#8a1cff")
+    t.right(angle * 2)
+    
+    build_tree(t, new_length, shorten_by, angle, "#ff7e1c")
+    t.left(angle)
+    
+    t.penup()
+    t.backward(branch_length)
+    
+tree = turtle.Turtle()
+tree.hideturtle()
+tree.speed(0)
+tree.setheading(90)
+tree.color('green')
+turtle.bgcolor("black")
+build_tree(tree, 40, 3, 15, "red")
+turtle.mainloop()