Thank you for viewing! (*ˊᵕˋ*) This is called Archimedes' compass, and it can be used to draw ellipses ☆☆ Why would someone think of this!? Amazing! We've increased the flexibility of the pen holder so that it can hold not only pencils, but also oddly shaped ballpoint pens and even design knives. You can freely move the two rotating axes within a certain range to adjust the amount of flattening of the ellipse! ❁ Long side: Maximum of about 100mm ❀ Short side: Minimum of about 35mm Adjustable in 1mm increments. There may be an error of about 0.5mm with the compass itself due to tilting, etc. |ω`) Pins are provided as an aid to draw stable ellipses by fixing two points. Please be careful not to get caught on clothing or fingers. If you intend to give it to small children, the usability will be reduced, but it can be removed, so please let us know. (_ _) As shown in the photo, we can change the pins to non-slip material for an additional 25 yen d('∀'*) We will provide supplementary explanations, such as the derivation of the ellipse equation from the geometric coordinates of this compass, along with diagrams, in a HOPPEN explanation ٩(ˊᗜˋ*)و Some assembly work is required, but it can be done without any problems by elementary school students and women! Material: ABS This product is white. This material is used in many LEGO blocks and plastic products around us. It contains rubber components in its composition, so it is flexible and resistant to impact and bending. Please note that other colors are used in some common explanations. Color: White #FreeResearch #FreeCrafts #Ellipse #Compass #InterestingStationery