Update README.md

README.md

 # Sheet Prototyping
 
-
+<img src='img/ur-rotation-end-effector.png' height=400px>
+<img src='img/wiz-and-rotary.jpg' height=400px>
 
 ### Materials
 
+* Cardboard
+* Paper
+* Polypropylene
 * Steel
 * Stainless
-* Aluminum: low series.  3003.  <a href='https://www.onlinemetals.com/merchant.cfm?id=753&step=2&top_cat=60'>Online Metals</a>
+* Aluminum: Must be a formable series, like 3003.  <a href='https://www.onlinemetals.com/merchant.cfm?id=753&step=2&top_cat=60'>Online Metals</a>
 
 
 ### Design tools
@@ -18,4 +22,5 @@
 	* <a href='https://www.youtube.com/watch?v=_CPkUqedqhA'>sheet metal gems part 2</a>
 * Rhinoceros 'UnrollSrf' Command
 * Solidworks sheet metal
-* 123D Make
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+* 123D Make
+* ExactFlat
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