A rhythmic approach to mathematics

In practical terms it is about stitching coloured thread to produce patterns of pursuit curves as the envelopes of the lines of thread. However, in 1906 the idea of children doing any sort of mathematical activity for fun must have been extraordinary. The preface is by Mary Everest Boole, George Boole's wife, and evidently a friend of Somervell. My copy bears the autograph "Ethel Home, from E.L. Somervell, Oct: 1906" "What shall be, is.. "