So I was ghost-hunting today and noticed that certain fragments are only available on the paradox mission, but only when that mission is the daily heroic story. Kind of like the black spindle, which got me thinking that bungie has not only hidden stuff in the game, in space, but also in time, which parallels a larger theme exemplified by the vex, who can transport themseleves through space and time. Anyway, really cohesive design, kudos to bungie for working on the meta-level.