Hey Jim,
It's actually a detail from a stained glass window designed by Frank Lloyd Wright with a simplified tube diagram imposed on it.
The center of the design is dominated by a wide diamond shape about 3 inches wide and an inch and a half high. Through the center of that diamond is an X with the same angle as the diamond. In fact, if you were to split the X in the center and connect the two triangles, the resulting diamond would be the same as the central one. Above the X is an inverted V which also has the same angle. If you combine these three elements you there are 3 inverted V's ,..starting from the top, the one that forms the top of the diamond, the inverted V, then the one that forms the bottom of the X. The spacing between the top of the diamond, the inverted V and the bottom of the X are equal.
The central diamond is enclosed on the left and right by a vertical line that meets the two end points of the diamond and extends to the top and bottom of the face. The inverted V also ends at those lines but the ends of the X continue past those lines about half an inch. There's also a short horizontal line that extends out from the ends of the diamond to an imaginary line from the ends of the X.
From the top of the diamond there are 3 vertical lines. One extending from the top point of the diamond and wrapping across the top. The other two vertical lines also extend across the top and are about half and inch to the left and right of the central line. These three vertical lines start again at the bottom of the diamond with the two outside ones extending to the bottom of the front. The one in the center is the center line of an inverted "T" which goes down about half and inch. Also, the lines that form the bottom of the diamond extend past the bottom point of the diamond to the two vertical lines forming a small bow tie shape.
There are two more vertical lines that go down almost to the bottom starting at the arms of the inverted "V". There is a horizontal line that connects each vertical line that goes down the full hight of the front panel with the two lines coming down from the inverted "V". Just a little higher than those horizontal lines is a short horizontal line that connects the two outside lines that start at the bottom of the diamond.
Coming out of the right side of that short horizontal line is an inverted capital "L". The bottom of the bow tie shape, the inverted T and the inverted L are meant to form a stylized tube with the T being the plate and the L being the cathode.