Thank you, all.
Ianwater, unfortunately I haven’t any more pics of this project. It was built in 1986 and the misfortunes of an estate matter prevent me from having many more pics of many more projects from the 80’s & 90’s. However, I can give you a brief description; the partitions beneath the staircase form a right angle to the rear, as an adjoining hallway is at the back of the entry way. The molding forming rectangular panels beneath the horizontal molding, divide the space in equidistant thirds, and thus the triangular forms are aligned above the rectangular ones, carrying the uniform division to the inclined plane of the stairs above. If you still require more information, send me an e mail address and I can provide you with a simple sketch.
Best regards.
MikeMangini