Here's a heptagonal (seven-sided) stage with two entrance doors, marked X and Y.  The seating areas can be used in different ways depending on the needs of the production. •If just the yellow seats are used, all the audience is on one side of the stage and in full view of both doors, rather like a traditional proscenium stage; scenery could be erected behind the stage.  •If the red, yellow, and green seats are used, we have more of a thrust stage; some of the audience may not be able to see one door or the other.  •If the yellow, green, blue, and purple seats are used, with most entrances taking place at door X, we have an asymmetric thrust stage.  •If  the yellow and purple seats are used, the audience is on both sides of the stage, arena-style, but can still see both doors.  •And using all seats (including a sixth section in the lower right that I didn't draw) gives us a theatre in the round.