I love dead zones. I know it's weird, but that's the only time I get to indulge in my cell phone games without distraction. In New York City, the ultimate dead zone is the subway. When the train conductor announces that we?re ?experiencing delays due to tunnel traffic. Please be patient,? other people may groan, but I?m thrilled. ?Awesome! I get to complete this level now.?

My latest obsession is Enigmo. This is a cool, crazy game that started out as an OS X program before showing up as an iPhone/iPod Touch app. You enter a surreal, futuristic setting to redirect water, oil and lava?in the form of blue, green and red droplets?into vases by dragging drums, sponges and other objects into their paths. Sounds simple enough, but as you level up, the challenges become mind-bending. Enigmo's advanced levels appear to defy gravity, as buckets start showing up above the streams, behind walls and sometimes even inside a maze.

The UI is gorgeous, optimized for the huge 3-inch iPhone screen, and it doesn't take long before the glowing, colored liquids are bouncing and cascading all over the place like a light-and-fountain show on Mars. It's a beauty to behold, and oddly soothing as the brain goes into hyper problem-solving mode.

This is highly addictive stuff (especially if you?re a wannabe engineer like me). The self-satisfaction of solving these seemingly impossible puzzles is tough to give up, even when the subway reaches its destination. Or when you have to switch to another program. Enigmo saves completed levels, but not one that's in progress, so if you go look up an address or write a text, you?ll have to start it over again when you come back. Small price to pay, though, for having total mastery over the laws of physics.

At $1.99, Enigmo's sale price offers a lot of play for a ridiculously cheap cost. And once you've finished the 50 supplied levels, you can connect to Pangea Software directly from your phone to download custom levels made by other players.

This little game has become my most used app ever. I just tap the water droplet icon on my home screen, and I've got plenty to keep me happy until out of the dead zone.