This is Blackbox, an old puzzle game. To play, click the arrows on the edge to shine a light into the box. The light will either exit the box at another arrow (the colors will change to match), return out the same place (the arrow will reverse) or not exit the box at all (the arrow becomes an X). The placement of four hidden balls inside the box determine this. If the beam of light hits a ball it doesn't exit; if it travels near a ball it changes direction to avoid it:

. . | . .
. . | . .
. . - - -
. O . . .
. . . . .

In the case that a beam would have to turn while in its starting space, it counts as a return. The goal of the game is to find all four balls (click to place them) with a minimum number of clues.

If you want to play the game on your machine locally, download it. The same JAR file will also work as an application. If it doesn't work at all, you'll need the latest version of Java to run it. If you have a Mac, it will work, you just need to configure Java 5.0 properly in Safari.

This was made in roughly a weekend using a Mac, Eclipse, Java 5, and a library I built specifically for prototyping games. If you'd like to use my library also, send me an email. The source is in the JAR file, but I'd appreciate it if you asked me before using it.