I would model it as follows
Modelling in the plan window as though it was in elevation (this is known as 'slabifying' refer to the GDL Cookbook or Object Making with ArchiCAD book if you have them. You can get the Cookbook here...
www.archicad.ca/?p=84
Use a mixture of walls and slabs for the "Ram Horn" each set at the required height. Once you have one horn done just mirror a copy to create a complete set.
You then select the elements that make up your "Horns" and view them in 3d with an ortho Elevation view, viewing it so that you see a 'Plan" view of the slabs. Save it as a library object. Insert into your model.
The central 'Pot" in the middle can be modelled with the
Profiler tool with the base for the pot being modelled with a couple of slabs.
Assemble the Horns and Pot into the correct position and you are done. If you going to slap a lot of these around your Project then I would save the entire assembly as a Library Object, its up to you.
If the horns need to be curved both in elevation and profile then use a Complex Profile instead of Slabs/Walls.
Best of luck.
AC versions 3.41 to 25 (UKI Full 5005).
Using AC25 5005 UKI FULL
Mac OSX 10.15.7 (19G2021) Mac Pro-2013 32gbRam AMD FirePro D500 3072 MB graphics