Circular circles, straight lines, happy times. Latest version comes with circles meant to roughly fit on engineering paper squares. Additionally added a rectangle for drawing beams.

I personally designed this based off the circle sizes I use most frequently. It also works as a nice straight edge for everyday notes and homeworks.

The CAD file is also on onshape in the link below if you would like to copy the document and make any changes. https://cad.onshape.com/documents/302ecec7faebb2d34c7b192a/v/b6cb81ce5b89bc197b355b38/e/7a9b369ae3fe97c7461df105