Here are some Bump Jigs (chunky try squares) I made to help me do layout work on my leather projects. They can be used for any layout work, anywhere you need a square that sits flat on its side, and is thicker than the material you want to use.

The Fusion 360 file is parametric, you can use the Modify > Change Parameters tool to adjust the dimensions of the square. Controllable dimensions are: the length of each arm, the width of the arms, and the height/thickness of the tool.

I have also included a few different sized .stl files for those who do not wish to download or use Fusion 360.

The stls are named with dimensions in the following format: Arm 1 Length x Arm 2 Length x Width x Height. All units in millimeters.