How come oil and water pipelines have right angles in them?

At intervals they have a series of right angles. is it to keep them from freezing? how does that work?How come oil and water pipelines have right angles in them?
For thermal expansion.





The right angle can flex slightly - like from 88 to 90 to 92 degrees and allow the pipeline to expand and contract with changes in temperature of the pipe.





Those changes can be from environmental conditions (ambient temperatures, solar input) and from temperature changes in the pumped fluids (heavy oils are heated whereas gasoline is not and many pipelines carry mulitple products sequentially).





Slight changes in length in a straight pipeline would causes huge deviation laterally. Consider a chain (like the ones that attach the pen to desk of the post office) a bit less than taut. A tiny fraction of a inch change will cause the chain to be straight or, alternately, sag even more.How come oil and water pipelines have right angles in them?
You're talking about those zig-zags they put in the pipelines, and it's to provide flexibility along the length of the pipelines to allow for temperature-induced expansion-contraction. In fact, pipelines are not actually bolted solidly to the support foundations, so they can slide freely length-wise. Otherwise, damage to the pipes can occur.
Long runs of pipe have loops or ';U'; shaped additions that allow for expansion and contraction of the pipe.