Cornelius Cardew instrument

Cornelius Cardew (1936-1981) is not especially well known for being an instrument creator, but nestled in his 1968 Schooltime Compositions, found at the British Music Collection, is a simple diagram of an instrument to be constructed an used in performances of the work. Although simple, the diagram itself is detailed enough to enable reproduction of the instrument at a later date, and shows a “cork tipped mechanical device” next to a “metal sound source”. The latter object looks to be a bell of some kind but since it is not specified as such can be safely assumed to be replaceable with any metal sound source depending on the performance situation.
What is important here is that we can reproduce the instrument from the diagram should we wish to - something which is sadly missing from a great many composer-built instruments. Cardew has therefore provided the wherewithal for his Schooltime Compositions to be recreated and re-performed in their entirety by future generations.