What you describe could be considered parametric design software. There are a few programs that will do as you require, but you will likely discover that they also have a 3D component. Even the simpler ones such as SketchUp will allow for 3D use, but you don't have to use it. Keep all your sketching in one plane and you'll be all set.
Consider to perform a search on YouTube for SketchUp tutorial to see how it works.
I'm a fan of a parametric drawing program known as SolveSpace. It also is free and has a few tutorial videos on the YouTube.
Well, shucks and by golly, I almost forgot one of my more commonly used programs, strictly 2D drawing, known as Inkscape.
With Inkscape, you can position the guides at 10 mm intervals and use them to position your lines. Alternatively, you can use the slightly more complex method of creating clones and spacing the clones at 10 mm intervals. Either way, it won't get simpler than that. Go into preferences, change the units to mm and cast away!