This is a simple design of an icosahedron that functions as a bookend if filled with cement or a planter if filled with soil.
For full instructions and a design tutorial, check my Instructables post here:
https://www.instructables.com/How-to-Make-Modern-Geometric-Bookends-For-All-Skil/
The Instructables link above includes free plans to make it out of sheet metal or raw cement.
The model is parametric and can be easily scaled to any desired size!
(The model on the left side is for 3D printing. Sheet metal body on the right side is for cutting sheet metal)
The author marked this model as their own original creation.