This is a great project and pupils love it. It uses 12cm squares of plywood but can be done with hardboard though this is not ideal, you could also use acrylic or foamex for details such as eyes or letters but pupils generally are happy to saw away using good quality birch faced plywood for hours. It can be shortened to just a practical task for a few weeks or spread over a whole term, and this helps to improve all the basic skills as pupils are drawing and peer evaluating, modelling their designs, learning to use the tools (a mini keyring project) Then they can evaluate their skills and produce the final design to produce a quality product. It never fails to please and pupils always take them home as a permanent 'memory aid'. Everything is quantifiable for assessment purposes and assessment criteria based on a "making progress & Even better if" is included on key pages -winner.
It is a full project, involving research of existing products, producing a specification, creating designs that are then modelled in card to produce templates. Then a few practical sessions producing a keyring. Evaluation of skills learned, then on to the final design manufacture and final evaluation.