Experts at the Massachusetts Institute of Technology are designing a durable laptop computer that will cost about $100. MIT Media Lab leader Nicholas Negroponte hopes to give the machines, which would be durable, flexible and self-reliant, to needy children around the world. The machine’s A-C adapter would double as a carrying strap, and a hand crank would power them when there’s no electricity. They’d be foldable into more positions than traditional notebook PCs, and carried like slim lunch boxes. For outdoor reading, their display would be able to shift from full color to glare-resistant black and white.