Half-Box (Green) can be exhibited in two states. In its ‘closed’ state, it appears to be a simple triangular block. When opened, it presents a square surface. When the work was originally shown, the viewer was invited to open or close the box. The idea that the work depends on the active intervention of the viewer can be seen as Craig-Martin’s ironic response to the idea of the ‘autonomous object’ associated with Minimalist artists such as Donald Judd and Sol LeWitt.