The Willits House is the first house in true Prairie style and marks the full development of Wright's wood frame and stucco system of construction. Although the Willits House has two stories, it is a more complex shape, consisting of a rectangular central space with a rectangular wing projecting from each side of that space. This is a standard design feature for most prairie-style houses, in addition to low roofs, elements that run parallel to the ground and extend out beyond the frame of the house. Wright used a cruciform plan with the interior space flowing around a central chimney core and extending outward onto covered verandas and open terraces. The plan of the house is a windmill style, as seen with the four wings extending from the fireplace in the central core and the movement from each wing being along a diagonal line. Wing two contains the great living room with high windows and a walled terrace. The dining room, extended by a large porch, comprises the third wing; the fourth, towards the rear of the house, contains the kitchen and servants' quarters. Wright incorporates diagonals into several other places in his design – the dining room has a prow-shaped end bay and another prow-shaped projection, the reception room has a similar prow-shaped bay, the art glass light over the entry stairway is rotated 45 degrees, again emphasizing the diagonal, and the terminating piers of the porte cochere are offset from the end wall by 45 degrees.