I guess these occur more in fantasy novels. The genre my novel would fall into is probably 'fantasy and horror' or 'historical fantasy'. I've had to put a couple of ideograms in as small illustrations (think Wilbur Smith & Warlock, or Tolkein with Elvish script). It's not excessive, just two small pictures about 1cm x 1cm within 20,000 words. I'm not sure if this is OK. One is to depict a sigil and one is used to depict the 'imaginary/connecting' lines between a set of constellations. Just wondering what other peoples thoughts are on these? I know the obvious response is you should be able to describe it with words, but some things need to be really specific and accurate and they are hard to describe beyond tracing lines in the night sky.
I don't really see a problem including them - as you say, there is plenty of precedent for it. Illustrations or diagrams are no longer particularly common in books, but they are far more prevalent in the genres you mention - maps are often quite useful or even essential, and if there is a rich culture of symbolism in your world I would think seeing those symbols would be helpful. I think the biggest question is how and where you include them, but if you ever get to the publishing stage an editor will advise on that.
yes, it's done... but you probably wouldn't include them in the ms, just indicate in brackets what will go where...
