Based on the text, it appears the keys in the Kisanji are being likened to a support structure similar to stems. While in practice, their description is visually closer to multi-colored paper strips or stripes. Since stems can be both seem as support and can easily be likened to a support structure with a similar shape to a stripe, I think most readers will be able to make the connection. While the stripes would make them understand the visual idea faster, but the idea of support won't be as apparent as it would be with a stem.

Image links:
Stem:
https://media.geeksforgeeks.org/wp-content/uploads/202209221...

Strip:
https://onelittleproject.com/wp-content/uploads/2020/03/DSC_...

Stripe:
https://i.pinimg.com/736x/0b/be/34/0bbe3477b3eb56cc2b1699a9e...

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Note added at 5 hrs (2023-05-24 12:07:52 GMT)
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Sorry about the non-editable typo. I am adding a better revised version of the affected part of my text as such:

Since stems can both be seen as a support and can easily be likened to the idea of a support structure with a shape similar to (vertical) stripes, I think most readers would still be able to make the connection and understand the the text.