The spider walked across the top of my computer with complete confidence. He didn’t hesitate–he was on a mission. I was busy writing. We almost managed to ignore each other. But before I knew it he was dangling from the top of the screen, descending towards my desk like a seasoned mountain climber. Maybe he was trying to entomb my screen? Did he think there was some chance of catching a quarry attracted by the light of my Mac? I have to say I didn’t want to find out.