H Cannon

h cannon (also known as HSTSD) is a setup that consists of a T-Spin Double and a Super T-Spin Double. This opener notably forms the shape of a lowercase h. It was first discovered by garbocan and later popularized by Caboozled_Pie.

Setup
The bare minimum for this setup is the S piece to perform the first TSD and another S piece to setup the overhang for the STSD. Below are some examples:

Variant
There are a few ways to complete the first TSD, but many opt to freestyle stack by this point; here are some examples: