. >> i want to point out the most beautiful pieces of sidewalk and would aboutingent reese much this is gorgeous and perfectly done absolutely gorgeous, when are the elements that make this so good and comply. under the ada the building department requires a landing on the outside of any entry that's level, considered quarter inch per foot or 2 percent. as you know this san francisco we have a lot of sidewalks that are a lot steeper than 2 percent. the trick is, how do you acomidate a landing a flat landing at an entry in the middle of a sidewalk that happens to slope -- >> away from the building. and longitudinally at a slope like this? it wasn't easy but we created guidelines with regard to feathering out the sidewalk. >> you can look at this one. here we are. here it's 2 percent. this is this meets the definition of level. more or less. 2 percent and meets the slope. what was previously a sloping sidewalk but you see over here they raise today a bit to make a smooth transition to the existing sidewalk. >> also raised the curb to make it flatter in this direction and the feathering