# Is there a name for a 3D shape that looks like a circle when viewed from one axis, a square from another, and a triangle from the third?

The shape can be constructed by taking a cylinder with its height equal to its diameter and cutting a triangle out of it when viewing it from the side with the base of the triangle matching one end of the cylinder and the opposite point of the triangle in the center of where the opposite end of the cylinder was.

Is there a name for this shape?

Like this?

It has three Forms depending from which side you look:

• Very nice. Just curious how did you draw this? Sep 30, 2016 at 1:49
• I used Mathematica's RegionPlot3D and added three constraints for the three planes accordingly. In the end i just increased the plotpoints and voilá Sep 30, 2016 at 10:22
• Yes exactly like this. Does this have a name? Sep 30, 2016 at 17:17

The shape displayed in Julien Kluge's answer may be seen as a special version of a cylindrical segment, which MathWorld describes as the solid cut from a circular cylinder by two (or more) planes. In any case, it can be made by removing two cylindrical hooves from a cylinder. No idea whether there is a distinctive name for what is left, but the name cylindrical wedge is already reserved for the version with only one slanted cut through the cylinder base, examples of which are the cylindrical hooves mentioned above.

It is called a chisel tip. A round chisel. However, not all chisels are round.

For a circular base it is like a pencil lead sharp chisel line edge cut/ground by sandpaper that way for drawing thin lines. Elliptic arc intersection lines on side view appear together with square border.