A ruler assembly comprising a ruler having a top extending along a ruler width and a ruler length. The top has an inner top surface and an outer top surface. The assembly has at least one side wall extending along the ruler length. The side wall extends from a side wall bottom edge to a side wall top edge proximal to the outer top surface. The outer top surface comprises a plurality of step surfaces, each having a step height measured from the side wall bottom edge to the side wall top edge of each of the plurality of step surfaces. In some embodiments, the inner top surface and the inner side wall surface define a ruler cavity configured to removably couple to an insert ruler.