The mug tree is an ideal first practical project for BGE level. It includes using marking out tools, cutting out joints and using the pillar drill. It could be extended to introduce other tools like the plane.
Rather than jumping straight into cutting the parts for the mug tree, this lesson series starts with a simple joint.
The mug tree could also be used as an early 3D modelling project. The simple shapes and repetition required to build the parts introduces pupils to the 2D sketch, extrude and extrude subtract tools. Other tools like fillet and chamfer can also be introduced if required. It also includes assembly.