As practice coding with writing functions, conditional expressions,
and loops, we develop a small tic-tac-toe video game via 7 versions,
where each version after the first adds a little code to the previous
working version.
<p>
  Please download tic1.R, listen to the screencast tic1.mp4, and run
  tic1.R yourself. Study and modify tic1.R and ask questions about it
  until you understand it. Then repeat this process for versions 2, 3,
  ..., 7.
<p>
  Later you will do homework implementing Connect Four, a similar game.
<p>
  <a href="tic1.R">tic1.R</a>, <a href="https://go.wisc.edu/2kvfbd" # "tic1.mp4
					     ">tic1.mp4</a> (4:40)<br>
  <a href="tic2.R">tic2.R</a>, <a href="https://go.wisc.edu/3wfm9a" # "tic2.mp4"
				  >tic2.mp4</a> (2:35)<br>
  <a href="tic3.R">tic3.R</a>, <a href="https://go.wisc.edu/xsb2eq" # "tic3.mp4"
				  >tic3.mp4</a> (4:22)<br>
  <a href="tic4.R">tic4.R</a>, <a href="https://go.wisc.edu/411jgy" # "tic4.mp4"
				  >tic4.mp4</a> (5:39)<br>
  <a href="tic5.R">tic5.R</a>, <a href="https://go.wisc.edu/1lzq3f" # "tic5.mp4"
				  >tic5.mp4</a> (2:31)<br>
  <a href="tic6.R">tic6.R</a>, <a href="https://go.wisc.edu/260vxq" # "tic6.mp4"
				  >tic6.mp4</a> (4:12)<br>
  <a href="tic7.R">tic7.R</a>, <a href="https://go.wisc.edu/52j677" # "tic7.mp4"
				  >tic7.mp4</a> (14:06)<br>
<p>
  Develop your own programs incrementally, saving working versions of
  increasing complexity as you go. That way, when something breaks and
  you can't get the current version working, you can go back to the
  previous working version as a help to debugging the broken version.
  You always have a working version when a homework deadline or your
  boss appears.