Skim Cannon (also known simply as Kerr Loop) is a 35-piece (5 bag) loop usually consisting of a TSS -> TSD -> skim -> TST -> skim -> TSD -> PC, with a 94.25% PC chance with 3 minimals if using TETR.IO 180 spins.
It was first constructed by Kerrmunism in July 2021, later being improved upon in March 2022 for the 5 Million Blast game mode in TETR.IO.
It is notable for having a decent build chance (50.00% or 83.33% with mirrors), a high PC chance with low minimals and including many opportunities for COOL clears in the 5 Million Blast game mode.
When performed optimally, it is one of, if not the most efficient loop for the game mode, with some runs under 175 blocks.
First Bag
The first bag is always constructed like this. You'll need Z before I and S (or S before I and Z if you're mirroring it.)
Second Bag
The second bag will be constructed using one of the below methods. While the two lead to different shapes, they will resolve the same way.
Third Bag
The third bag will be constructed in some combination of the pieces shown here. The specific order isn't relevant, but depending on the order you will usually either arrive with a skim into T-Spin Triple, a Mini T-Spin into Triple into Single or a Mini T-Spin into a Tetris.
If your O comes before your I in this bag, you have a small chance of being able to continue the loop by building something like this.
From this point, you would build the rest of the fourth bag on top of this board, then use your I piece in hold to get down and continue the loop.
Fourth Bag
The fourth bag will always be built like this, resulting in a T-Spin Mini Single into a skim. You may need to use a S spin (or Z spin with mirror) to get the S or Z into place, as well as sometimes needing a 180 spin to get the L (or J with mirror) into place.
The different colored J piece (L if mirrored) represents it needing to be placed after the T.
Fifth Bag
You now have a 94.25% PC chance with 3 minimals. The first minimal may need a Tetrio specific 180 T-Kick to resolve the PC.
