After observing Miller's description of the physical properties of the courtroom what specific details make the room "forbidding"?Act III

The room is empty, but plainly decorated and has a serious, dark air about it.  There is sunlight, but only through the upper windows--it is not cheerful.

The heavy beams jut out, plain boards make up the walls, and there is a long meeting table and chairs in the center.  The starkness gives the feeling of lack of hope for those who enter, especially when they face the serious and solemn faces of the judges and accusers.

It is dark, lonely, too serious, and intimidating.  These things make up the quality of "forbidding" as used by Miller.