I have a displayed equation that uses colored boxes to represent omissions. The colors match a corresponding model. Normally I would use the general omission symbol in displayed material not sure I can here. Would love your input. I have attached a sample.
The sample you helpfully provided shouts "use textures" to me. Three different tactile textures to correspond to the three different printed colors should give the student the best access to the concept being taught.
I fully agree with your reservation about using any general omission symbols. How would you distinguish the pink, green, and blue areas? How many symbols should you use in each area? I think there are no good answers to those questions.
Are you able to use tactile area textures to transcribe this material?
PRCVI ([Canadian/Vancouverian] Provincial Resource Centre for the Visually Impaired) has a section of its website dedicated to tactile graphics, with some files of complex tactile graphics available for download as well as a few instructional materials (some more up-to-date than others).
TGTV is a series of online videos from APH devoted to tactile graphic design. Each episode in the ongoing series will address one or two aspects of the design process involved in adapting a print graphic (for example, from a textbook) into a readable tactile image.
In addition, you may post questions in the Tactile Graphics Forum of Ask an Expert.
Thank you for your response. Using textures had occurred to me. It is just something I haven't seen before. Glad to know I can do that. I have used the APH Library a lot but was not aware of the Canadian image library. I will check it out.