Fractal

Fractals are also known as TSD stacking. This is one of the most common T-Spin Methods used in multiplayer. Be wary that it can be difficult to build these without using T-blocks in the stack, therefore presenting significant risk in the event that you don't get enough T-blocks in time for the execution. This pattern can be used to make a stack indefinitely high, but setups stacked three or higher are rare.

Fractal 1
Two or more T-Spin Doubles layered above one another in the following even shape.

Fractal 2
Fractal 2 is a similar idea to Fractal 1, however the shape is uneven. Notice that with F2, the hang must be on the correct side to avoid blocking the hole.

Two T-Spin Doubles
By changing the position of the overhang, you can change from fractal to an imperial cross.