About this 3D model

Hi! Recently after I watched CNC Kitchen video, he talked about calibration cube and how he doesn't like design of it. After some thinking I thought that making a calibration cube which would eliminate a few problems would be.. nice, so I got to work. T his calibration “cube” is 20x20x20mm. If you want to have more accurate results, you can scale it up. T he “cube” has rounded corners and seam on its edge, to not mess up the measurement because of over extruded corners. T he “cube” doesn't have flat surface at the 15mm mark. Instead it's on an angle to remove the possibility of wrong measurements because of over extruded top surface. If you have any ideas on what i could change to make it better, please make a comment! ?