Print-in-place stool.
Available in two sizes.
55cm and 37cm.
The stools are designed so that you only need support for the small stool, which I've already added manually.

0.4 nozzle
4 walls
0.16 or 0.2 layer height
15% infill gyroid
4 top/bottom layers

Large version:
High load capacity. 150 kg shouldn't be a problem.
Printed in PLA.
Print all parts. The seat and base of the large version will be glued in place afterwards using superglue or UHU ALLPLAST. To do this, remove the print from the plate. Telescoping it out with a little force, and glue the lid and base in the extended position. The tolerances are selected so that no support is required. Due to the amount of material, the filament spool needs to be changed once.

Small version:
High load capacity. 90 kg was tested. No problems.
Print all parts. Remove the manual support from below. Now press the inner and outer rings together. Rotate them all the way around so that the guide pins can be released (you may hear a slight cracking sound). Using a hammer handle, tap the inner ring together on the floor to allow the seat to extend. The gap is designed so that not too much force is required.

When extended, secure the floor with superglue or UHU ALLPLAST.