The Stairs pattern, also known as Kaidan (階段積み, kaidantsumi), is usually the first form learned by beginners due to its intuitive structure.
The idea behind Stairs is to place chains next to each other so that falling Puyo connect to each other on the side.
The most popular form of Stairs. Uses space efficiently with low color-conflict potential. The Transition is also easier to make on this than on other Stairs forms.
Another form of Stairs that's used almost as often as 3-1 Stairs. A bit harder to make with a higher color-conflict potential. It's usually used in conjunction with GTR or with dropsets in Fever mode.
This form of stairs has an incredibly high color-conflict potential. It's basically impossible to build on the second floor without breaking something. If you find yourself using this form in some places, there was probably a better way to build your chain. Still, there are a few applications, such as Tailing or Power Chaining.
The above three Stairs forms are interchangeable. A useful fact to know if you made your chain really terribly.