My son dragged me into it. I didn’t want to cross my eyes. It hurt. I kept trying, hoping to please him. Yet, I failed. Only he could turn two images into one 3-D image by crossing his eyes.
Once he conquered that technique, he moved on to a video. There, a girl named Mara rapidly flashed up complex onscreen images and, in each one, my son found a super-small thing wro...