This is a three dimensional drawing of a cone in space. It is made by the use of a sculpture that consists of a blackboard with a string nailed to it with markings at equal intervals. This string is used to draw concentric circles with chalk. Each circle is bigger than the previous one by a constant amount.
Each time a circle is drawn, the blackboard is moved forward 5 cm. This leaves a trail of lines, made by the residue of the chalk drawings. The length of these lines is the same as the diameter of the circles on the blackboard. These lines of chalk dust make a triangle shape on the floor.
The resulting markings on the ground and chalkboard show the sections of a cone made by circles of increasing size.