The plumber's rule states that if there are two identical pipes, they must be connected. In Connect the Pipes: Connecting Tubes, the same rules apply. And to make it easier and easier for you to find the same pipes, they are painted in different colors. Initially, you will see colorful circles on the playing field. It is necessary to connect two circles of the same color to each other. As soon as you start drawing the line, it will turn into a thick pipe. The entire space should eventually be filled with pipes and they should not intersect with each other in Connect the Pipes: Connecting Tubes.
