"
The graphic shows the activity named "Pour Cement" represented with a box. Inside the box you can read the text "WBS = No. 12, Pour Cement and Duration = 2 days"
In each corner of the box there is a small box with a value inside.
At the top left corner you have the value for Early start (ES) for the activity which in this case is 23.
At the bottom left corner you have the value for Late start (LS) for the activity which in this case is 24.
At the top right corner you have the value for Early finish (EF) for the activity which in this case is 25.
At the bottom right corner you have the value for Late finish (LF) for the activity which in this case is 26.
So we have the values: ES=23, EF=25, LS=24, LF=26.