Margaret Roberts Triangle & Circle 3A 2017 (jarrah timber, graphite, found wall, energy of visitors and gravity) at The Drawing Exchange in Adelaide Central School of Art. The Drawing Exchange is an exhibition of 22 wall drawings in the Adelaide Central School of Art and the National Art School in Sydney, curated by Luke Thurgate and Maryanne Coutts. It is open art-school hours from 11 August till the end of September, 2017. Photo: Sam Roberts

Triangle & Circle 3A is an enlarged version of Triangle & Circle 3. It is enlarged to accommodate rulers the same width as the jarrah of the timber floor nearby to where it is installed—intended as a built-in connection to the immediate location despite being derived from a planning process that used triangles and circles in a distant place (in Italy in the seventeenth century).

The enlargement of Triangle & Circle 3, and the need to locate it on the (un-enlarged) found 3m x 2m wall provided, reduced its visibility to only one part of its triangle and just one of its rulers. This transformed it in effect into a work that is unique to its location in the Adelaide art school, while maintaining the potential for interested viewers to visualise how the part connects to the whole—something we are well practised in doing in daily life (eg when navigating buildings or roads).

That single ruler, however, can still be moved by visitors as it was originally intended—to make the half-circles used to design the footprint of Borromini's Sant'Ivo Alla Sapienza. Its capacity to move also shows the work's collaboration with the actual space of its location, through the energy of gravity and of visitors who are willing to physically interact with it.

The ruler also has a red underside, made apparent by sanding. Jarrah is a tree native to southern Western Australia, and its characteristic redness suggests the colour of much of the nearby interior of the continent that Adelaide feels quite close to due to its semi-desert climate. The red underside contrasts with the frontside of the ruler, painted black and marked by its previous use as a board of someone's timber flooring. The red is also the colour of the iron oxide used in many earlier works.

Thankyou to Matt Taylor who found the jarrah timber and assisted in installing the work and its lighting, as well as demonstrating its movement in the images above.