MS Office has a “bevel effect” that applies to any shape.
This feature expands the number of possibilities for representing things.
For instance, when I prepare diagrams with containers (variables inside of RAM; device drivers inside OS, etc.), concave shapes make the relation evident and also beautiful. It is ready in seconds, no fancy geometrical manipulation needed.
The distinction between flat and bumped (concave/convex) surfaces is useful in several contexts.
Thanks to all developers for LibreOffice, it is great! Looking forward for having more shape effects and possibilities.