meets Data and they exchange opinions on the relative value of logic and emotion, and share mutual impressions of Next Generations Captain Picard (who for Spock is a model of logical behavior, and for Data is a model of what it means to be human). Critics such as Ina Rae Hark have noted this encounter between two non-human characters in which they summarize their contrasting attitudes to humanity, Data embodying Spock's ideal of pure logic, while Data aspires to be more human. Scotty appears in TNG Season 6, Episode 4 "Relics". Recycled footage from the original series episode "The Trouble with Tribbles" is used extensively in Deep Space Nines time-travel episode "Trials and Tribble-ations". In addition to extensive archival footage of cast from the original series, actor Charlie Brill (portraying Klingon spy Arne Darvin) appears in both new and archival footage. The episode was designed to coincide with the 30th anniversary of the original series. Critic Matthew Kappell notes that the new episode simultaneously "parodies and valorizes" the original series, highlighting the discontinuities between two eras of Trek while trying simultaneously to weave them together. William Riker and Deanna Troi from The Next Generation appear in a flash-forward to the future in "These Are the Voyages...", the final episode of Enterprise. This episode was widely criticized by both cast members and fans for playing more like a Next Generation episode to the point of being an inappropriate wrap-up for the series. Film-to-television crossover In the Voyager episode "Flashback", events from the film Star Trek VI: The Undiscovered Country (1991) play a pivotal role, and are reenacted with the same actors, thus allowing George Takei to reprise his role as Hikaru Sulu. The episode contains the added revelation that the character of Tuvok was on Sulu's ship Excelsior at the time. Critic Lincoln Geraghty cites this as an example of Star Treks ongoing propensity for reverential recognition of earlier versions of the series. In bit of rather glaring discontinuity, the character of Lieutenant Dimitri Valtane is shown to be both alive at the end of the film and dead in the episode. Actor Tim Russ, who portrayed Tuvok, also made an appearance as a bridge officer from the same fictional time period, serving on the Enterprise-B in the feature film Star Trek Generations (1994). Television-to-film crossover The film Star Trek Generations brought Kirk and Picard, Enterprise captains from different centuries, together