Does anyone know if it is possible and, if so, how to use a symlink to share a module or theme between two different ddev projects?

The problem I am trying to solve is that I am working on a contributed theme. I would like to make css changes to the theme and see how they effect two or more different sites with different content and different configuration. 

I suppose my other option is to simply copy the changes from one project to another each time I make changes.

Comments

I don't use DDev, but Lando, but I think the approach is fairly similar. When you are using the website within the container then the file root is /app/ (may be different in DDev) so you wouldn't be able to go outside that.

I've never tried, but that is my understanding, limited as it is.

Different DDEV projects can communicate with each other. Here is a little information on that:

https://ddev.readthedocs.io/en/stable/users/usage/faq/#can-different-projects-communicate-with-each-other

But, I think that @yorkshirepudding might be correct, that linking via symlink may not be possible.  I understand the reasons why it would be difficult, but it's not clear to me that there isn't anyway to build some kind of virtual bridge between projects.