# 05. CircleFrame – Wedge tool

The wedge-shaped drawing tool has a rounded edge that matches the curve of the circle in the CircleFrame. This rounded side covers an arc of 45 degrees. You can keep it in place with one or two fingers in the round hole in the tool and press it against the edge of the circle.

Two sides of this tool end in a flattened point. One of these sides is straight and ends in a very small point that serves as a pen-stop. This pen-stop exactly coincides with the center of the circle. With this straight side you can draw both the center and the radius of the circle.

The other side of the wedge is slightly curved inward. This side has pen-stops that indicate the radius per centimeter seen from the center of the CircleFrame. The small block between the penstops of 2 and 3 centimeters is used to position the compass base.

### Drawing pie charts

The wedge tool can be used to draw pie charts, which are often used to present information in fields such as mathematics, economics and geography. The quantity that each sector represents corresponds with an arc of a certain number of degrees. By determining the angle between two radii on the inside of the circle, you can draw the pie chart very accurately. Many other mathematical concepts in which degrees and angles play a key role, such as vectors or polar and trigonometric functions, can be explained and drawn as well using the CircleFrame.

Figure 1. Measure the required angles along the circle and use the straight side of the wedge tool to create a pie chart.

### Combining the compasses with the CircleFrame

Another function of the wedge tool is to position the compass in the center of the Circle Frame. You can achieve this by placing the wedge tool anywhere against the edge of the circle with the compass base against the flattened tip of the wedge. The center of the compass base now hooks around the pen-stop at the tip of the wedge tool.

By slightly turning the base counterclockwise, it will catch the small protruding block on the curved side of the wedge. This way, the compass base is exactly in the middle of the circle. By removing the wedge tool and placing the compass arm into the base, you can now draw a circle precisely in the center of the CircleFrame.

Figure 2. Position the wedge tool along the edge of the circle (step 1), position the compass base and turn it so it rests against the wedge tool (steps 2 and 3) and remove the wedge tool (step 4). The compasses are now perfectly positioned in the center.

You can also combine the compass with the edge of the circle. The indents per five degrees are semicircular and have the same diameter as the needle of the compass. After placing the compass base on the CircleFrame, you can slide the needle of the compass into one of the indents along the edge. The center of the arcs are now exactly on the circle. By drawing multiple arcs along the edge of the circle, you can create intriguing repetitive geometric patterns.

### Drawing the hands of a clock

Around the circle of the CircleFrame, multiples of 30 degrees are indicated by drop-shaped indentations. These make up for the twelve hours of the clock.
To draw a clock hand, you can use the wedge tool. Along the rounded side you will find grooves at an angle corresponding to 1 minute, or 6 degrees. The longer groove of 2 centimeter indicates the position of 5 minutes or 1 hour later. After placing the wedge tool with the rounded side against the edge of the circle and aligning the straight side with one of the hour indications, you can measure the minutes and draw the hands of the clock as radii and have it set at any desired time.