Rhombi - Cube - Octa Dome Simplified Version with X1 subdivision; 21 ft. 2 x 6 frame with a Cupola and double sliding glass door.
On this example, the equilateral triangles are made flat, keeping the 6 struts and 1 Connector Hub in each. One above the entrance is fitted with a hexagon opening for a skylight or window.
Front view shows the long axis of the Cupola, which is a vertical extension (Type 1) of an enlarged square pyramid, 20 inches above the dome top.
Black and white illustrations show details of the cupola and window areas. >>