I'm not clear on how this would happen on wayland as I haven't done any development on it yet, but with X it would be tricky since the server still has the window hierarchy state for event routing etc.
If you simply mirrored redirected windows in triplicate all over the place in the compositor, it wouldn't magically make the window manager and X server aware of all those areas as being windows to manage and route events at. You'd just have these ghost windows that can't be directly interacted with as first-class windows.
You'd just have these ghost windows that can't be directly interacted with as first-class windows.
But that is what the GP asked for, not full duplication.
Though if you want duplication it might be possible by creating a window over the duplicated area that the compositor does not render but still grabs all input events that are then forwarded to the original windows via XSendEvent.
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I'm not clear on how this would happen on wayland as I haven't done any development on it yet, but with X it would be tricky since the server still has the window hierarchy state for event routing etc.
If you simply mirrored redirected windows in triplicate all over the place in the compositor, it wouldn't magically make the window manager and X server aware of all those areas as being windows to manage and route events at. You'd just have these ghost windows that can't be directly interacted with as first-class windows.
But that is what the GP asked for, not full duplication.
Though if you want duplication it might be possible by creating a window over the duplicated area that the compositor does not render but still grabs all input events that are then forwarded to the original windows via XSendEvent.
For a presentation, the non-interactivity might even be more of a feature than a bug.