In a perfect world, when it snows out, you shovel your driveway while the snow is virgin. Then you drive off to work.In the real world, sometimes you don't have time to shovel, and drive across your snowy driveway to get to work. Later, when you get back to shovel, you find the tracks left by your tires have solidified into an ice-like matrix. The weight of your vehicle has compressed the tracks, and your snow shovel slams into them and stops.This Hammerhead Snow Shovel was designed for exactly that situation. The polycarbonate shovel head is reversible (it's on a hinge), and one end has teeth molded into it. This toothed edge tears right through hard-packed snow. Once the tracks are broken up, you can reverse the shovelhead and shovel normally.Interestingly the inventor, engineer Shane Swanger, came up with the idea while using an old, broken snow shovel. This design had ribs molded into it for strength, but the front lip had broken off. While using it, Swanger observed that the jagged ribs cut perfectly through the hard-packed stuff. These run $22 for an 18"-wide model, and $27 for a 20" version.