Pipes can connect to other pipes, of any material. if a pipeline has more than one kind of pipe, then the speed of items through it will be that of the slowest pipe in the path.
Pipes connect visually to each other and to containers
Pipes are optimized to be more performant than hoppers or other mechanisms to move items around
Regular pipes pull items from the surface they are placed on. Copper, Iron, and Gold pipes are crafted with their respective ingots. Turn copper into oxidized copper pipes by throwing in a cauldron, or crafting with a water bucket.
Corner pipes push items into the surface they are placed on -- regular pipes push items into corner pipes. Copper, Iron, and Gold pipes crafted with their respective ingots. copper -> oxidized copper pipes with a water bucket or cauldron.

pipes for transferring items. fully configurable, nice visuals