I’ve been using my kids’ playhouse as my work-in-progress during the lessons. The proportions aren’t quite right, and there is a slide on one end and a set of swings on the other I hope to model once I learn a bit more.
This is the actual final challenge - the torii (gate) at Itsukushima, in Japan. The base shapes are all primitives, though I looked up how to transform individual faces/edges to simulate the curves and create the other shapes.
Both renders from Cycles.