Yeah, Time Piece is a great little short. Jim himself did the cel animation (the colored particles dancing around), while Don Sahlin handled most of the stop-motion effects (like the blooming flowers). Trivia notes: You'll have to pause quickly, but Frank Oz plays the office messenger in the workplace sequence (he's billed as "Frank Oznowicz", a slight misspelling of his given name), and though his face is slightly more obscured in the You Tube version, Jerry Juhl plays the bartender in the Night Club sequence. A fun short film, trippy and with serious themes but still very funny (and much better than the overlong "The Cube" to my mind).
And if you really want trippy, look on Youtube for other old videos uploaded by the same guy (animator Nate Pacheco), including a brilliant Wilson's Meats Meeting Film which must be seen to be believed.