Michi.nu has released
And Round Again, a puzzle game where the goal is to create as many loops as possible by connecting segments that appear on the screen. It costs $15 to register; you can download and try it out for free.
The full game features different game modes, difficulty levels, minigames and customization options. A hundred different pieces can be used to create loops, and the game features an extensive bonus and combo system. Stores can be recorded for posterity online, and it features secrets, surprises and unlockables.
System requirements call for Mac OS X v10.3 or later and 32MB VRAM.