I would most likely use docstrings as a reminder for later when I have to pause what im doing and continue my work later on.

tile.py

@@ -1,4 +1,5 @@
 from turtle import *
+from math import sqrt 
 
 def draw_tile(size):
     "Draws one tile, which can be repeated to form a pattern."
@@ -6,22 +7,27 @@ def draw_tile(size):
     draw_squiggle(size)
 
 def draw_tile_outline(size):
-    pencolor("#dddddd")
+    pencolor("#FFBD88")
     square(size)
 
 def draw_squiggle(size):
-    forward(size/4)
+    diagonal = size*sqrt(2) 
     pencolor("black")
-    left(90)
-    quarter_arc_right(size/4)
-    quarter_arc_left(size/4)
-    quarter_arc_left(size/4)
-    quarter_arc_right(size/4)
-    left(90)
-    fly(size/4)
-    left(90)
-    fly(size)
-    left(90)
+    left(45)
+    forward(diagonal)
+    back(diagonal)
+    left(45) 
+    pencolor("#FFBD88")
+    forward(size)
+    pencolor("black")
+    right(135)
+    forward(diagonal)
+    pencolor("#FFBD88")
+    penup()
+    right(135)
+    forward(size)
+    right(180)
+
 
 def fly(distance):
     "Moves without drawing."