LEGO Architecture Robie House Building Instructions page 8

To further emphasize the horizontal lines of the house, the horizontal joints of
the red-orange, iron-spotted Roman bricks were filled with a cream-colored
mortar and the small vertical joints were filled with brick-colored mortar. From
a distance, this complex and time-consuming process creates an impression
of continuous lines of horizontal color and minimizes the appearance of
individual bricks.
Robie House was one of the first residences to incorporate steel beams directly
into its design. These strong beams in the ceilings and floors were necessary
to create the cantilevered balconies, which appear to be suspended in mid-air.
The brickwork (FLWFDN)
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As the steel beams also carry most of the building's weight, the exterior walls
have little structural function, which in turn allowed Wright to fill them with large
numbers of doors and windows. More importantly, the steel structure eliminated
the need for internal structural columns and walls, thus underlining the overall
open plan favored by both Wright and Robie.
"Both Mr Wright and myself were highly in accord on every line to the last inch.
And we agreed that there should be no deviation whatsoever from these
specifications." Frederick Robie, on working with Frank Lloyd Wright.
The entrance (FLWFDN)