I taught at a school in the late 70s / early 80s when computers were first coming into use. Our head of IT was tearing out his already thinning hair because he was being given classes of 20 when only about 8 computersn were available. He went to the LEA's computer advisor and asked if any money for more computers was available. This educational wizard replied that there was not, but that he had a stock of CARDBOARD KEYBOARDS which could be made available so that every pupil in the class could practise pressing the right keys!

Thinking of that reminded me that my mother, who was a very occasional pianist, had a cardboard piano keyboard so that she could practise without making any noise.

Surely these would be available cheaply!