The photograph shows all four corners of the quatrefoil (now numbered 42.a to 42.d) together.
Presented by John Ruskin to the Ruskin Drawing School (University of Oxford), 1875; transferred from the Ruskin Drawing School to the Ashmolean Museum, c.1949.
Taylor, Gerald, ‘John Ruskin: A Catalogue of Drawings by John Ruskin in the Ashmolean Museum, Oxford’, 7 fascicles, 1998, Oxford, Ashmolean Museum, no. 033
Ruskin, John, The Ruskin Art Collection at Oxford: Catalogue of the Rudimentary Series, in the Arrangement of 1873, ed. Robert Hewison (London: Lion and Unicorn Press, 1984), cat. Rudimentary no. 42, RUD.042
Ruskin, John, Instructions in Practice of Elementary Drawing, Arranged with Reference to the First Series of Examples in the Drawings Schools of the University of Oxford (n.p., [1872]), cat. Rudimentary no. 42
Ruskin, John, Instructions in the Preliminary Exercises Arranged for the Lower Drawing-School (London: Smith, Elder, 1872), cat. Rudimentary no. 42
Ruskin, John, Instructions in the Preliminary Exercise Arranged For the Lower Drawing-School (London: Spottiswoode, 1873), cat. Rudimentary no. 42
Ruskin, John, ‘Rudimentary Series 1878’, 1878, Oxford, Oxford University Archives, cat. Rudimentary no. 42
Ruskin, John, ‘The Ruskin Art Collection at Oxford: Catalogues, Notes and Instructions’, Edward T. Cook and Alexander Wedderburn, eds, The Works of John Ruskin: Library Edition, 39 (London: George Allen, 1903-1912), 21, cat. Rudimentary no. 42
The figure in the lower left hand, and that in the higher right hand angle are to be copied by all students, for rapid pencil exercise. The originals, as examples of sculpture in fluent & current line, are quite insuperable.