So let's go now with another type of construction industry relationship, which is the finish to finish relationships. This one is also common in the construction industry. The finish-to-finish relationship requires the following. It requires the finish of the successor to occur at least lag days after the finish of the predecessor. Again the finish to finish relationship requires the finish of the successor to occur at least lag days after the finish of that predecessor. And also here you can find some examples where you have a lag of zero. For example, let's also go with the first one here. Let's say we are tying the steel rebar and then we going to place the forms. So, imagine we have a wall, all the steel rebars. And, the workers are working to put all the forms all around the steel rebar of the walls. And at the same time another labors are tying all of this rebars together. That right practice is to finish the two activities at the same time. You're going to finish placing the forms and tying all the rebars from all the up all the down, all the levels of the wall. And as you can see here the early finish time of both activities are the same, 33. It's not necessary to start at the same time as we can see here. The tie rebar starts at day 30, placing the forms start one day after the tying of the rebar, which is still fine. What we are highlighting here is the finish to finish relationship to these two activities. So let's take another example by highlighting a lag as we can see here. These two activities has a finish to finish relationship with a lag of three days. As we can see here placing the wall rebar and then we completing the wall forms, three days after we finish placing the wall rebar. Because if you would think about it from construct-ability point of view. Sometimes you want to clear the area from placing the rebars, either from your workers laborers, or highlighting it from lowering from a crane, and placing the rebars. And then you ask your workers to continue working on that, three days after to make sure that this is the forms will be done after you finish placing the rebar. So this an example of a finish to finish relationship. Another examples of a finish to finish relationship is, we cannot finish, let's say, the back filling activity of a trench until we make sure that laying of the part activity is complete. So this are another examples and I encourage you to keep thinking about other examples of finish to finish, start to start relationships. So what we covered here so far is that mainly three types of construction activities relationships from the finish to start, from the start to start, from the finish to finish relationships. And we give examples with lag equal zero and other examples would lag equal one day, two days, and three days and more.