enter image description here

I try to create an illustration containing certain items represented by coloured boxes (exhibits 1 and 2), with the colour distinguishing different types of items. Assume that the look of these boxes (shape, colour, …) is fixed. Now I need to create a third type of box that should represent an item whose type is not known, but that is either of the blue type or the orange type¹. I am struggling with how to best do this.

Here is what I considered so far and why I am not happy with it:

  • Exhibit 3: Splitting the fill colour of the box, making the question mark white. The part of the question mark on orange ground is not well visible.
  • Exhibit 4: Splitting the fill colour of the box, making the question mark black. The part of the question mark on blue ground is not well visible.
  • Exhibit 5: Splitting the fill colour of the box and the question mark. The question mark is difficult to recognise as one character.
  • Exhibit 6: Using some average fill colour between blue and orange. As the two are complementary, this does not make sufficiently clear that only blue and orange are possible states and that this is not about some state in-between the two.

All the above contain the question mark as I consider some indicator other than the fill necessary to indicate that the state is uncertain. This indicator does not need to be a question mark however.

My question is: Is there any better way to visualise this that I am missing?

In case this matters: This for a scientific poster (i.e., it should be readable from about 1 m distance), with each box being roughly 1 cm wide. The background is white. I cannot finetune the colours of the printed results but have to live with what I get.

¹ A case that is actually both, orange and blue is clearly excluded by context.

  • 1
    What about using #3 but changing the font to something really heavy and extended? The font seems a bit thin but your idea of mixing the blue and orange makes perfect sense in this context; the question marks makes it logical too and easy to understand. Otherwise a black drop shadow with 0 distance could be nice too if applied on the icon/character. type.co.uk/preview/imgs/…
    – go-junta
    Jul 2, 2015 at 11:05
  • 1
    +1 for the really good examples and extensive background of question. This really is an exemplary question.
    – PieBie
    Jul 2, 2015 at 12:03
  • I disagree strongly with the two-colors-in-one approach. Without a key this conveys "both" not "neither." You are actually dealing with a 4-value system here: option 1, option 2, no option determined (that is, addressed, but inconclusive), and no value.
    – Yorik
    Jul 2, 2015 at 14:48
  • @Yorik: Both does not make sense in the context (I added this to the question); think of the colours representing hot and cold. I do not see the problem with it meaning neither – using a third colour would do that.
    – Wrzlprmft
    Jul 2, 2015 at 15:04
  • I won't belabor it too much, but in the case of hot and cold, it is an axis or spectrum, so "both" actually makes a lot of sense and a two-colored icon would work. Temperature is not a two-value excluded middle like you describe. "Indeterminate" temperature is not the same as "neither hot nor cold" and should not share the colors of either value.
    – Yorik
    Jul 2, 2015 at 16:05

7 Answers 7


I think you don't have many more options that make sense. It's logical to use the 2 colors in the box and the question mark makes the message clear too.

But maybe you could play with the angle of your colors, and the font style too.

Examples for icon blue and orange

On the first one, I simply changed the angle and it seems to interfere less with the question mark. It really changes the style! Maybe a thin font would be more visible with that angle too. The font on this example is Museo 900, the same as the second icon.

On the 3 others, I used your angle for the colors, but different fonts and effects

  • Museo 900 font with no effect
  • Museo Sans Rounded 900 with a drop shadow
  • Verdana Bold with an angled solid black outline

Edit: Added the different angle with the 2 last effects.

Another example


Consider adjusting the colors so that a black or a white question mark will be visible on both of them, but keeping them the same at the borders. For example:

question mark thingy

You can still see the original colors on the borders, but the black question mark is now visible on the lightened interior (I just used the Brightness/Contrast tool in GIMP).

(In hindsight, the border probably should have been wider, so that the original colors would be more visible. Oh well, it's just an example.)

  • The only bad thing about this approach is that it creates a white later for this type that other types don't have Jul 2, 2015 at 22:24

Agree with go-me's answer.

Another approach could be a 'playing card' approach, and invert the questionmark both in colour and position, like thus:

enter image description here

  • For my opinion....it is correct given an upvote at your answer also.
    – Sebastiano
    Jul 30, 2019 at 22:51

The logic symbol for "xor" is commonly....

enter image description here

You could use this symbol .....

enter image description here

Ultimately this is all a matter of opinion and preference though. Whatever works for you, works :)

If it's all about clarity.. don't overthink it....

enter image description here

Or maybe....

enter image description here

There are really dozens of ways (if not hundreds) to visually represent this. I think this is just too broad of a question and it'll be pure happenstance if someone hits on what works in your opinion.

  • You're right it's xor not or. But what you are asking is referencing an XOR choice - exclusive. "Or" is inclusive. The box is either blue or orange. If it's blue, orange is excluded and vice versa. Or am I reading wrong? I'm not a mathematician... I'm just going by visuals.
    – Scott
    Jul 2, 2015 at 19:55
  • Based on Scott's idea, it could be nice though if the box was split into 4 quadrants like his second example. Maybe it's worth trying, it looks like this on some card games (eg. Uno for example, but it has 4 colors.)
    – go-junta
    Jul 2, 2015 at 19:59
  • @Scott: You are correct, I brainfarted there. Still, the problem arises that the symbol is not sufficiently well known to have any effect.
    – Wrzlprmft
    Jul 3, 2015 at 4:31
  • Well.. if clarity is the primary concern..... I've edited the answer. :)
    – Scott
    Jul 3, 2015 at 4:42

I'm no way a professional, but when i'm dealing with an issue of this type (white isn't visible on the light color, black isn't visible on the dark color), i always do the same thing: i put the text in white, with a black border. You are sure the text will be visible on all colors. You could take you picture number 3, adding a black border to the question mark. Give it a try!

edit: Here is an example now:enter image description here

  • Hi Aye1. Good answer. Since this is a primarily visual website, it's always a good idea to include an example of what you're trying to say. But I guess @go-me beat you to it anyway.
    – PieBie
    Jul 2, 2015 at 12:06
  • I know, i know, you are 100% right, but i'm currently at work and can't do that right now (or poorly under Paint). I wanted to bring a fast answer though.
    – Aye1
    Jul 2, 2015 at 13:34
  • Yeah, I know, got the same problem sometimes. Just leaving the comment for future passers-by.
    – PieBie
    Jul 2, 2015 at 14:06

I was just thinking you could go with the opposite angle so as to prevent the "clash" between the diagonal line and question mark ending (top end). + also I've tried with non-zero thickness of the delimiting line. I'm an amateur.

another attempt


Where the context clearly prevents the icon being interpreted as "orange and blue" it must represent "orange or blue". As such, there is no need for the question mark at all in your case.

Leaving out the question mark allows a possibility of more than two colours to be more easily shown — a question-mark may not make it easy to see the potential colours.

Where the context doesn't make that clear, then other answers here which incorporate the question mark necessarily bear consideration; but the small size of the box in your case (1cm square) makes less clutter desirable. "Less is more" has many applications!

If a question mark is needed, I would prefer that it come from the same font family as you use for the rest of your poster series (I guess this is for display of a paper at a conference), which may mean that that also has to be reconsidered.

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