Dynamic double strectch rectangle. Inside rectangle doesn't follow outside rectangle equal.

[Loewi]

I'm modeling a dynamic block.
It represent a simple floor plan chimney.
The dynamic block has six stretch actions.
Three stretch actions are displayed in the properties menu.
Two strectch actions have grip points.
The total width and length.
Tree stretch actions are chaind.
They stretch with the wall thickness action.
Unfortunately they won't move equal. 

Drawing1.dwg

Edited November 23, 2021 by Loewi