'Heart Knife' is an early example of a Scottish artist working in a semi-abstract style derived from Cubism. It was painted during Crosbie's final year at Glasgow School of Art. However, despite the use of abstract shapes in the picture, the shading on the vertical shape shows Crosbie's use of depth. The work also shows the influence of Surrealism. Crosbie later recalled that the painting referred to his problematic and unhappy relationship with his father and to: 'damaging, acute disappointments.'