a challenge architecture backdrop background berlin building business dynamic facade fit fitness futuristic germany glass modern office offices outlook perspective reflection reflections shape shapes stair staircase stairrail stairs stairway steps stone structure structures stylish success training translucent transparency transparent upstairs upwards way to go window windows workplace abstract arena asphalt athletics begin block brown competitive contest cover curve determination distance endurance fast field focus game abundant appearance bright color coloration colored colorful colors colour coloured colourful colours contrast curved decorative distinctive edges fitted fitting geometric geometrical interconnected interlinked light multicolored multicoloured patterned patterns perspectives plastic rounded rows shaped spiralling spirals surface surfaces surfacing texture textured textures thick thin twists vibrant wallpaper architectural barrier constructed edged exterior external fancy flat gaps linear lined lines rectangular secure security slabs smooth stonework strength style uneven variation varied various wall circles lighting round curled curls hooked hooks pieces plentiful coloring colouring historic large local-stone old patchwork random randomly-coursed rock rocks rough rugged rural shade shadows sharp solid stone-walled stones strong sunlight sunshine variations variety