This last plate needs to be cut following a line that indicates the contour of the wall. If the wall is not straight, the plates are not parallel to the wall or there are pipes in the way the contour marker can be used to draw that line in one single smooth movement. To do so you need to place the plate that needs cutting upside down on and parallel to the previous plate (figure 2). To prevent relegation you can use for example a rubber mat between the plates.

Place the contour marker on top of the plate that needs to be cut in a way that the guide can follow the side of the plate (figure 1 ; at point C). The head of the contour arm (figure 1 ; at point A), with help of for example a spring, will now touch the wall. On top of this head there might be a wheel (figure 1 ; at point B). If you move the contour marker along the side of the plate using the guide the contour arm will move in and out as it follows the contour of the wall. The contour arm is directly connected with the drawing arm (figure 1 ; at point D) which makes the same movement only in opposite direction. For example by using cogwheels or pulleys. Attached to the drawing arm there is a guiding tab against you need to place your pencil. The exact spot of the guiding tab is depending of the shape of the contour marker because it must indicated the exact same spot that matches the point where the wheel hits the wall. This means that the distance between the point of the wheel that touches the wall and the guide must be the same distance between the guide and the guiding tab. In figure 1 this spot is indicated with an E.

When moving the contour marker along the plate using the guide and holding a pencil against the guiding tab, the contour marker will draw the right line on the bottom of the plate. Because the plate is upside down the contour will appear negative (mirrored) on the plate. But after cutting it will fit when you flip it over with the right side up. The advantage of this method is that you do not need to preset the contour marker on a certain width of the plates. The width of the plates does not matter and they may have also different widths. So you can use a remaining piece of a plate to make it fit.

The wheel at the end of the contour arm (figure 1 ; at point B) may be adjustable in height so it follows the exact line where the plate will touches the wall. The guiding tab (figure 1 ; at point E) must be adjustable because sometimes you want to leave a little space between the wall and the plate. Also the profile of the side of the plate can require adjustment of the guiding tab.

De contour marker can also be used to copy the contour of a plate on to another plate (figure 3). Therefore you need to put a plate with a straight side upside down on top of the plate that you want to copy in a way that the straight side nowhere overlaps the plate that needs to be copied. Place the contour marker on top of the plate with the guide against the straight side. Lower the wheel at the end of the contour arm in a way that is hits the side of the plate that you want to copy. With help of for example a spring the wheel will be pulled against this side. The way to draw the line is the same as written above (negative). When using a guiding tab attached to the contour arm you can also draw a positive copy (figure 4). Of course the plate does not need to be upside down then.

Both above descripted methods can be combined when you have to make fit a plate in a spot with no single straight side. Both arms can also be integrated into one. In addition the mechanical arms can also be replaced by laser or laser guided electrical arms or the distance can also be measured with sound waves.