The cube felt rubbery, although it didn't strictly exist. As I moved the pencil-like mouse in my hand, a cursor moved too in the virtual room where the cube sat. A little manoeuvring and the cursor was beneath the cube. Move the pencil (called a "phantom") upwards, and suddenly there was the sensation of weight, and the cube moved upwards on the screen. With a little practice, I could flip it upwards and catch it. The surface seemed to give, like rubber; the weight felt like a small ball, perhaps a golf ball. A few minutes later another cursor appeared,...