perhaps the prospect of tacos , an especially favorite food , made me so happy the evening after the boy scout pow wow that i invented a favorite game of mine -- it had no namewhose purpose was to cross each row of large rocks in my mothers rock garden , she collected those on our trips to abandoned ranches and mines in arizona , and i discovered that i liked to work my way across the stones , steadily and carefully , turning sharply and expertly at the end of the row and drop to the lower file of rocks , as though i were on a steep switchback track , bright angel trail , for example , like those i had seen in the book brighty of the grand canyon .