Various changes have been made to the basic set since the syndicated version's premiere in 1983. In 1996, a large video display was added center stage, which was then upgraded in 2003 as the show began the transition into high-definition broadcasting. In the mid-1990s, the show began a long-standing tradition of nearly every week coming with its own unique theme. As a result, in addition to its generic design, the set also uses many alternate designs, which are unique to specific weekly sets of themed programs. The most recent set design was conceived by production designer Renee Hoss-Johnson, with later modifications by Jody Vaclav. Previous set designers included Ed Flesh and Dick Stiles.
The first pilot used a vertically mounted wheel which was often difficult to see on-screen. Flesh, who also designed the sets for The $25,000 Pyramid and Jeopardy!, designed the wheel mechanism. Originally made mostly of paint and cardboard, the modern wheel mechanism is framed on a steel tube surrounded with Plexiglas and more than 200 lighting instruments, and is held by a stainless steel shaft with roller bearings. Altogether, the wheel weighs approximately 2,400 pounds (1,100 kg).
The show's original puzzle board had three rows of 13 manually operated trilons, for a total of 39 spaces. On December 21, 1981, a larger board with 48 trilons in four rows (11, 13, 13 and 11 trilons) was adopted. This board was surrounded by a double-arched border of lights which flashed at the beginning and end of the round. Each trilon had three sides: a green side to represent spaces not used by the puzzle, a blank side to indicate a letter that had not been revealed, and a side with a letter on it. While the viewer saw a seamless transition to the next puzzle, with these older boards in segments where more than one puzzle was present, a stop-down of taping took place during which the board was wheeled offstage and the new puzzle loaded in by hand out of sight of the contestants. On February 24, 1997, the show introduced a computerized puzzle board composed of 52 touch-activated monitors in four rows (12 on the top and bottom rows, 14 in the middle two). To illuminate a letter during regular gameplay, the hostess touches the right edge of the monitor to reveal it. The computerized board obviated the stop-downs, allowing tapings to finish quicker at a lower cost to the production company.
Although not typically seen by viewers, the set also includes a used letter board that shows contestants which letters are remaining in play, a scoreboard that is visible from the contestants' perspective, and a countdown clock. The used letter board is also used during the bonus round, and in at least one case, helped the contestant to see unused letters to solve a difficult puzzle.