Computer does not do thinking for you. The local planning board , if any, will have some say plus you have to also consider sewers, water, curb and gutters, open space etc.
OF course I’m assuming what you want to do. If you want to just fit size noted then it is a much different problem but even then roads may require other than nice rectangular size.
Just some thoughts or not?
Form usually follows function so once you under stand all the requirements off you go?
@mac7595 is right on the money. You can easily draw 40x40 or 30x40 rectangles in SketchUp and shove them around to create a layout, but first you need to understand all of the constraints on what you are allowed to do.