He played Mario Brothers a lot on the Nintendo set on the TV at home, and as he walked across the grass now, he thought of the invisible bricks that hung unsupported in the air of the Mario world. If a player didn't know about one of them, he would have the little Mario man run right on by, but a savvy player would know to have the little guy jump up at just the right spot - and bump his head on what had looked like empty air a moment before but was now a brick with one of the glowing mushrooms on it. Catch the mushrooms and suddenly you were big. And if it was a lily instead of a mushroom, and you caught that, you could spit fireballs.
He jumped now. Nothing. Empty air.
Last Call, Tim Powers.