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.