About 12 years ago when I was working for Graphisoft as an employee (as opposed be being a freelance like now) we had a company in Sweden where the guys were designing cruise ships with ArchiCAD. One guy sent me one level of a ship once and the ship was more than 300 meters long. I guess they appreciate the Shell and Morph capabilities of the program nowadays.
I don't know about people using it for playground equipment design but knowing the capabilities of GDL and the modeling tools I think it is feasible.
I know at one time I was using GDL to graphically solve geometrical problems like there was a large triangle with lines within it dividing it into many smaller triangles and you had to figure out exactly how many different triangles were in it.
Loving Archicad since 1995 - Find Archicad Tips at x.com/laszlonagy
AMD Ryzen9 5900X CPU, 64 GB RAM 3600 MHz, Nvidia GTX 1060 6GB, 500 GB NVMe SSD
2x28" (2560x1440), Windows 10 PRO ENG, Ac20-Ac27