Spiral was released with a 'sub-set', 121 timeshifted cards in addition to the 301-card basic set. After the set officially went public, Rosewater said that Wizards of the Coast had released the apparently conflicting figures by accident, but ended up just as happy to have done so after seeing the speculation they fueled. Time Spiral booster packs marked Wizards of the Coast’s then-new and current premium card distribution method, where premium cards replace commons, as opposed to replacing a card of the premium's standard rarity. Nostalgia Creature card types from previous block sets, such as Kavu, Merfolk, Thallids, and Slivers, returned, in addition to new incarnations of old cards. Eight keyword abilities from past sets also returned in Time Spiral, with some keywords not having appeared since 1997: Buyback, Echo, Flanking, Flashback, Madness, Morph, Shadow, and Storm. Old non-keyword mechanics like slivers, rebels, spellshapers, and nightmares also appear on new cards. There are also several cards that directly allude to older, well-known cards, such as the Magus cycle: creatures that are similar to the cards , , , , and . Planar Chaos Designed by Bill Rose (lead designer), Matt Place, Mark Rosewater, and Paul Sottosanti, and developed by Devin Low (lead developer), Zvi Mowshowitz, Brian Schneider, Henry Stern, and Mike Turian, Planar Chaos was tasked with representing the present in a set focused on the cycle of time. The design team considered a number of ways to represent an alternate present, including the introduction of purple as a new color. Eventually, the team chose to represent alternate realities where elements of the color pie were shifted, placing spell types and abilities into unusual colors. These alternate realities were epitomized by the set's 45 "color shifted" cards. Unlike their predecessors in Time Spiral, these cards were direct reprints of previous cards, save for shifts in color, land or color references in card text, card name, and creature type. Some of these are instantly recognizable by veteran players as reprints of extremely famous and iconic cards, like being a black reprint of the white card , or being a colorshifted version of . Others are reprints of much more obscure cards, and would not have been recognized as colorshifted without the altered border, such as being a reprint of and being a color-shifted . Color-shifted cards in Planar Chaos are distinguished by an altered version of the modern card frame; the