Swimming pool

Today my task was to to mark our a swimming pool measuring 2.5m x 3m. I made 8 profiles to help with my marking out. the first thing i done was to mark out a 2.5m line across the floor and put 2 profiles either end of the line so i knew where my line was, then placed to profiles diagonal to the first 2. I then marked out a 3m line and done the same profiles on that line (either side then diagonal) i done this again with a 2.5m line and a 3m line to create a rectangle shape. We now had tie string to the profiles, we tied the string to the same order we did the profiles(plus the diagonals) Now this was done i measured 30cm arcoss the string and 40cm across the diagonal piece of string, we then tied a piece of green string to tie the 30 and 40cm point together. If there measuremeant were right then the triangle would measure up as 30cm, 40 cm and 50cm, the 3,4,5 rule. one this was done to all 4 profiles we had finished the task.