diff --git a/Exercise0_3.xml b/Exercise0_3.xml
new file mode 100644
index 0000000000000000000000000000000000000000..1fa74afc6069d7e4a09b608995c455bc12e13835
--- /dev/null
+++ b/Exercise0_3.xml
@@ -0,0 +1 @@
+<mxfile modified="2019-01-30T07:09:38.666Z" host="www.draw.io" agent="Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/71.0.3578.98 Safari/537.36" etag="BUfr3SSnZvy8UPBv9Jpn" version="10.1.6" type="device"><diagram name="Page-1" id="13e1069c-82ec-6db2-03f1-153e76fe0fe0">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</diagram></mxfile>
\ No newline at end of file
diff --git a/Exercise0_4.xml b/Exercise0_4.xml
new file mode 100644
index 0000000000000000000000000000000000000000..d5764c158a6a0deaf6b1a511e091b1f972b264f8
--- /dev/null
+++ b/Exercise0_4.xml
@@ -0,0 +1 @@
+<mxfile modified="2019-01-30T07:15:26.758Z" host="www.draw.io" agent="Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/71.0.3578.98 Safari/537.36" etag="E7Desb7uam9BoP8EDwIc" version="10.1.6" type="device"><diagram name="Page-1" id="13e1069c-82ec-6db2-03f1-153e76fe0fe0">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</diagram></mxfile>
\ No newline at end of file
diff --git a/Exercise0_5.xml b/Exercise0_5.xml
new file mode 100644
index 0000000000000000000000000000000000000000..797908698dcb95e2d5d604715c1709270a0579df
--- /dev/null
+++ b/Exercise0_5.xml
@@ -0,0 +1 @@
+<mxfile modified="2019-01-30T07:22:10.296Z" host="www.draw.io" agent="Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/71.0.3578.98 Safari/537.36" etag="-3omJ6UlfSgF_9dJslu7" version="10.1.6" type="device"><diagram name="Page-1" id="13e1069c-82ec-6db2-03f1-153e76fe0fe0">7VlRb9s4DP41QZ862FbiJI9Ntmx3uN0V63oF7mWQbcYWqtiGLDfpfv1Rtuw4kpNlRZMMxQK0kSmKssmP1EdnQOarzUdB8+RzFgEfeE60GZD3A88b+kP8rwTPtWDsObUgFiyqRe5WcMe+gxY2aiWLoNhRlFnGJct3hWGWphDKHRkVIlvvqi0zvrtrTmOwBHch5bb0gUUy0VLXcbYTn4DFid56MtITAQ0fY5GVqd5v4JFl9amnV7SxpfWLhEbZuiMiHwZkLrJM1qPVZg5cubZxW71usWe2vW8BqTxmwTigAXXDYRB64+UwcK692sIT5aX2xUy5E8TA8zmanAVqFKuRfgL53HgNHyZXw3LF/2JL4CzFq1kOgq1AogXynmvx7VY2WydMwl1OQ7V0jXBCWSJXHK9cHGKIJcUlor3mnOYFC6pdHZQICEtRsCf4AkWNJCXNSql2mrcIqVRVZCDSplrnO5XdFQv1mNMA+KwN5Tzjmdo+zaoHKqTIHqERYoSd6tPONIhRWywZ5x3NRfVRcnyqBV0xrhLkXxARTakW62xwPX3dtxHlLE5RFmKYKyfacddQeAIhYdMRaRx8hAwDIJ5RRc+OXOfdqF6ks3aiQbrupECTAUkH/aNGkeq0i1vjW+jhQKPvSCQSC4l3IJ4UEH/D7g3BbtrU/F8CdBMLdPe/a9/bB2GLsEuA8D749PcD+XPpQ/LHZuH8F99//3LtWkC0IAdpdKO4jvIFp0WhQthFT70AIovqWI4qslKEcDglJBUxyEOswfZux32jPu9pmQBOJWJ4l8b1eFTvcJsxfIC9wRsTIyj14+lVXTJkGBr5u4Y801DtA8sQRoE+d9RypVDsv+GW/el9XOIcvC/i/Jz+kPyk/vSgPg7qJ9yiuY3xywFuE80HgcWwqKi++gcbdYsszUv1TZFRI9/nLHzE76uvlHOQ9MpKim2Vc35cX/eUiZ4c2Vs5PAMzrmuXDq+vdAxPVTmI7dkTlo6DZWFyybJgZrM/emFZcCeGIbPo7ykLr5UppIcJJxi7qv3FY7cMJajkWENQINybBCqLHq589vQYGb4jIzs9hj0gMEvv66XH8Jc5Wb0jUohcNIWM6I3NonVsCk0NQ66Zi690so7NfaZnOMkaSHcQdfvP3VdsFehKZVQaFHkFmrqJKHKaNm1EIqV6o3Wj7tBbLEvOC4nU+xo2uJQDzfN3CSCvLtUIWToqpbD+lmYSvqGdxiSKu1YtPFdn6Q6Cd3m8Jvddwq5FFtlW1YCFlN/oiRWLIrVNby3ZrTavUE5GYyO+Y/u0Jb5rJ4R3snLin6+cXKoMTH3zzRBxpo3kBST7x8ZOfaKO7RNVUlkq8uk56B/nGv/mAmh1sr7VbPKJGYq+xrdluOfJJ/sNzE2k2I2qeQ21ufpcskIy7A0oirEJcDheW4E6N9khRh/l9fQCbp83/ZN5c3qEN2vfOdlSy4uLO3JiA9OxeaPrndOVwzPyxgu2TGZtNv15dNNkMDHL0IlL/NB+gaabprovqn8CVO8XQl5GLI0V+GHdpsal+ybXiAPpITpuDxJe8FoBL7c/ONb+3/6oSz78Dw==</diagram></mxfile>
\ No newline at end of file