Add currently solved exerises from Chapter 16

thinkcspy/Chapter-16-Exercises/tree.py

@@ -0,0 +1,49 @@
+import turtle
+import random
+
+def color(branchlen, t):
+    t.pensize(branchlen/5)
+    if branchlen < 15:
+        t.color("green")
+    else:
+        t.color("brown")
+
+
+def getAngle():
+    return random.randrange(15, 46)
+
+
+def getLen(t):
+    return random.randrange(5, 15)
+  
+
+def tree(branchLen,t):
+    if branchLen > 5:
+        color(branchLen, t)
+        t.forward(branchLen)
+        angle = getAngle()
+        t.right(angle)
+        tree(branchLen-getLen(t),t)
+        t.left(angle * 2)
+        tree(branchLen-getLen(t),t)
+        t.right(angle)
+        t.backward(branchLen)
+        t.color("brown")
+
+
+def main():
+    t = turtle.Turtle()
+    myWin = turtle.Screen()
+    t.left(90)
+    t.up()
+    t.backward(100)
+    t.down()
+    t.color("brown")
+    t.speed(10)
+    t.pensize(5)
+    tree(75,t)
+    myWin.exitonclick()
+
+main()
+
+