Inverse round corners with Inkscape

Question

I am trying to reproduce these buttons:

Here is my attempt, but I don't know how to inverse the round corner to match the reference images:

Any idea is welcome.

Answer 1

Use the Bézier tool Shift+F6 to draw a closed path as in the example shown below

You can hold down CTRL as you use the tool to constrain the angles at the corners to 45 degrees, and for right angles at 90 degrees.

Then use the Edit Paths by Nodes tool F2 to curve the corner segments.