The Raspberry Pi and speaker that will be needed to make the clock chime every hour will need to have a way of staying inside the tower - even if the tower is lifted, and so I've used the Morphi 3D design app to create these two files.
The base of the tower will sit inside the cut out groove to add stability and also give an internal solid base. The cut out on the right hand side will allow the power cable for the Raspberry Pi to reach inside. The small speaker could sit on this base if the pupils choose.
This wil sit on top of the base piece (above). The groove will allow the Raspberry Pi to be fitted and stand at a slight angle. As with the other piece, the power lead will pass through the cut groove. The small speaker could also sit on this level if pupils decide they prefer it higher.