During the fall semester of 2008, I worked as a tutor for Fundamentals of Computer Science. At the end of the course, the students wrote their own implementation of Spacewar. When I took the course, we wrote tetris. So, I decided to give it a go, and the following is what I came up with:

I wrote this in scheme. Because we did not have an image rotate function, yet I still wanted to have triangular ships, I had to figure out the coordinates of all the three points of the ship, and then draw lines between them. The students used a big circle, with a smaller circle to represent the tip of the nose, as well as another one for a thruster, if it is on. Later, I added the control panel, as well as scoring and pausing. You can view the source code or play the game on a windows machine by running the executable in the zip. You should be able to run the scm file in Dr.Scheme.