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182 STRUCTURE AS ARCHITECTURE▲ 8.30 Seed House and Forestry Centre, Marche-en-Femenne,Belgium, Samyn et Associés, 1996. Exterior view.▲ 8.31 Shading increases at the splice positions of thetransverse arches.enclosing car parking at ground level, the roof of L’Umbracle functionsas a tree-lined garden. An arched and ribbed shade-structure enclosesthe whole area, and while its ribs are more slender and spaced furtherapart than those at Wohlen High School, one strongly experiencesits light-filtering qualities. Plants growing over the ribs in some areasincrease the level of shading.The interior structure of the Seed House and Forestry Centre, Marcheen-Femenne,also filters light and provides shade (Figs 8.30 and 8.31).Bentwood arches that span the building width support the completelyglazed ovoid form. Longitudinal arches provide stability in the orthogonaldirection. The combination of closely spaced arches and 100 mmwide members leads to significant areas of shade, especially where thetimbers are lap-spliced. Strong striped patterns of sunlight and shadowenliven the interior spaces.ReflectingStructural members screen direct sunlight but also provide surfaces offwhich it may reflect and then diffuse into surrounding space. The deepatrium beams of Louis Khan’s Philip Exeter Library, Exeter, already mentionedin this chapter, exemplify this interaction between structure andlight even though some commentators have queried whether the beamsachieve sufficiently high light levels at the ground floor level in the atrium.They point to the small quantity of direct light admitted through the partiallyshaded clerestory windows, and the low reflectivity of the greyconcrete beams.Roof beams in the Mönchengladbach Museum receive significantly moredirect light and, also due to their lighter colour, play a more influential