I have also realized that if I wanted to continue to pursue ruler attachments that, like the T square, would slide onto the ruler, but allow the user to draw lines at an angle other than 90 degrees in respect to the table edge, it would not be as simple as I thought (obviously). My first attempt was to turn the extrusion with the gumball, which kept the dimension of the ruler slot the same. However, when the boolean difference removed the slot, I realized that the length of the top and bottom of the slot had changed. So I was wondering if there was a way to keep the length of the top and bottom the same, using the same original curve. And the only ways I could think of doing that would change the width of the slot in between the top and bottom (the sides would be closer together as a result). The only way I can think of doing it would be to draw the slot curve in multiples in a row and create a hollow surface with them and I'm not quite sure how to do that.