Abstract: The sign includes a generally rectangular, pan-shaped opaque back, with its concavity presented forwards a generally rectangular, pan-shaped translucent front, frame or shell with its concavity presented rearwards, and means for fastening the back to the shell. The forward part of the shell is provided with at least one generally rectangular port bordered on at least two opposing sides with a ledge. Preferably lighting means is mounted on the back and any of several translucent sign faces are mounted across the ledges to span the port. Typical sign faces are: a translucent clock face with a clock mechanism behind and hands in front and a covering crystal that is transparent; a sandwiching of a translucent light diffuser, a color transparency and a clear cover; a translucent panel with rows of parallel grooves for removably mounting the characters for changeable messages; and translucent panels with messages or other advertising applied directly thereto.