Menahot 41: An Angel's Halakhic Reproof

Some unusual cases pose questions for tzitzit - for example, when a 4-cornered garment is folded in half. That is, is the garment obligated in the tzitzit or is the person obligated in wearing them? Plus, the plausibility of getting out of wearing tzitzit at all, followed by an encounter with an angel - who acknowledges that, in a time of God's anger, even unfulfilled positive mitzvot might be held against a person. Also, if a garment were made entirely of tekhelet, the tzitzit could be of any color, it would seem, except for the indigo plant dye. But wouldn't the tzitzit also need another color as well?