I'm sorry, but it seems to me, that you not correctly understand me. I will try to explain again. So, For Example, if some square has not line-up to centre square, but has line-up to others square, which has not line-up to centre too - then this squares (pipes) will not change the color to blue. Because this squares (pipes) is has not way to center square (source water). I'm sorry, againg, for my bad English. Its not my native language.