Escalier en coquille plate

facing=east,half=bottom,shape=inner_left facing=east,half=bottom,shape=inner_right facing=east,half=bottom,shape=outer_left facing=east,half=bottom,shape=outer_right facing=east,half=bottom,shape=straight facing=east,half=top,shape=inner_left facing=east,half=top,shape=inner_right facing=east,half=top,shape=outer_left facing=east,half=top,shape=outer_right facing=east,half=top,shape=straight facing=north,half=bottom,shape=inner_left facing=north,half=bottom,shape=inner_right facing=north,half=bottom,shape=outer_left facing=north,half=bottom,shape=outer_right facing=north,half=bottom,shape=straight facing=north,half=top,shape=inner_left facing=north,half=top,shape=inner_right facing=north,half=top,shape=outer_left facing=north,half=top,shape=outer_right facing=north,half=top,shape=straight facing=south,half=bottom,shape=inner_left facing=south,half=bottom,shape=inner_right facing=south,half=bottom,shape=outer_left facing=south,half=bottom,shape=outer_right facing=south,half=bottom,shape=straight facing=south,half=top,shape=inner_left facing=south,half=top,shape=inner_right facing=south,half=top,shape=outer_left facing=south,half=top,shape=outer_right facing=south,half=top,shape=straight facing=west,half=bottom,shape=inner_left facing=west,half=bottom,shape=inner_right facing=west,half=bottom,shape=outer_left facing=west,half=bottom,shape=outer_right facing=west,half=bottom,shape=straight facing=west,half=top,shape=inner_left facing=west,half=top,shape=inner_right facing=west,half=top,shape=outer_left facing=west,half=top,shape=outer_right facing=west,half=top,shape=straight