There’s a variety of types of pipes available. There’s 10 different types including rather nifty railway tracks, and a knobby type. They are specified with the -t flag. You can also use custom type of pipes.
The image below shows number 5 in the series.
The image below shows our favorite pipe type. It’s the aforementioned knobby variety.
There are other flags besides -t. These are listed in the image below. You can configure the number of pipes, their color, custom types of pipes, framerate, and even change the probability of a straight fitting (by default it’s 13, but can be set to between 5 and 15).