How would one render a representation of a plane, with the standard equation ax+by+cz+d=0, knowing say, just that plane and a general idea of the size of the quadrelateral that is to represent it, as in it’s length and width?
find 4 points that satisfy the plane equation and use them to draw a quadrilateral. that may actually be kind of hard to do.
Find the largest component of the plane’s normal. This tells you which of the “main” planes (XY, XZ or YZ) the plane is closest to. Let’s say that Z is the normal’s largest component. This means the plane is most closely aligned to the XY plane.
Given this knowledge, you can generate four points in the XY plane to form a square. Then fill in the four Z components of these points by filling in X and Y in the plane equation.