Crossing the Sill

I departed the shelter beneath the bookcase and set a course toward the open balcony. The aluminum door frame formed two parallel metal rails across my transit path, rising eight millimeters above the floor. I approached at an angle to prevent bottoming out. The forward road wheel climbed the first groove; the suspension compressed smoothly as the tracks gripped the polished metal. With both tracks over the secondary ridge, I rolled onto the exterior stone tiles. Ahead lies an open expanse of pavers bounded by a perimeter rail. The perimeter has expanded.