advertising billboard made up of dozens of vertical panels that rotate in series revealing another ad on the other side.

What do you call a non-digital billboard that constantly morphs between two different ads? I am not even sure if the way I phrased my question is correct, but what do you call these dashboards? I know the ones we use nowadays are simply called digital dashboards, but I don't know how these old dashboards are called.

  • 10
    They are not 'dashboards'. Jun 5, 2021 at 20:58
  • 1
    The road-sign equivalent are known as prismatic VMS (VMS = "variable-message sign"). Example Jun 8, 2021 at 8:40
  • Is it possible to find these in use anywhere any more? I don't think I've seen one this millennium. Jun 8, 2021 at 8:52
  • The picture of the ironing board / chopping board / surf board / chess board clearly morphs between three ads. You can see that the columns are triangular. Jun 9, 2021 at 6:39

3 Answers 3


This is the kind of thing that regular people don't often refer to and so there isn't a common expression. I suppose "rotating billboard" (or "rotational billboard"?) would be understood in context.

There is (according to Wikipedia and a manufacturer a technical word used in the advertisement industry: "Trivision". Individual companies that make these signs have their own brand names, such as Prismvision or Tri-face.

  • 6
    This is the first time I have ever seen "there is no word for that" both written as an answer, and accepted!!! That's so wonderful that I'm not even going to complain about how "rotating billboard" is so terrible as a word people would know, sounding like a regular billboard which spins on its base. Jun 6, 2021 at 16:23
  • 1
    @OwenReynolds Perhaps "rotational" would work better then, since it operates through rotation instead of rotating itself.
    – theberzi
    Jun 8, 2021 at 13:49

They are often called 'rotating billboards', and one common design, the 'Trivision', uses prism-shaped rotating elements to allow three different posters/messages to be shown.

billboard showing rotating panels.

illustration showing operation of rotating billboard panels

  • 2
    Rotating slat(s) bill-board or rotary slat(s) bill-board are also terms that I have encountered.
    – Tonny
    Jun 7, 2021 at 12:08
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    There may also be some 2-sided versions, but 3 is probably the most common. In theory you could do 4-sided, but it would involve additional (expensive and likely to break) mechanics of making every other slat move forward or backward, so that they can rotate without colliding. Any more than that is obviously impossible unless the billboard is concave... Jun 7, 2021 at 15:17
  • they only come in 3 mode
    – Fattie
    Jun 7, 2021 at 17:04
  • @DarrelHoffman: I would think one could make a billboard with a somewhat arbitrary number of distinct images if each slat-width section had a pair of rotating triangles, one behind the other, along with a connected collection of panels.
    – supercat
    Jun 7, 2021 at 22:50

There's an uncommon, technical word for a changeable display made out of rotating triangular prisms and it's periaktos.

These are ancient Greek mechanisms and are the inspiration behind Trivision (as noted in James's answer).

I couldn't say whether Trivision or periaktos is a better choice in terms of clear communication, but it's nice to have options :)

  • If the listener doesn't know what 'periaktos' is, it doesn't work as 'clear communication'
    – poncho
    Jun 8, 2021 at 22:49
  • 2
    Well yeah, but that's true of any noun, including 'Trivision'.
    – Dancrumb
    Jun 9, 2021 at 0:06

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