Making a plinth block using Carbide Create Pro (and other software)

You could have instead just re-taken the photos to make them square (I usually arrange such things on a gridded cutting board), then done the re-drawing in Carbide Create:

OpenSCAD is free, and it’s pretty obvious what the two lines of code do — presumably there are other 3D tools which could be used for this — I suppose you could buy:

and use that.

If you want me to send the file I made, let me know at support and I’ll put it on Google drive and send you the link (too large to e-mail).