Playing forever in Gravytris

Gravytris can be played forever assuming piece flip and gravity gun are available. Piece previews are not required.

Flat
Becomes 1210.

When worst case such as ZZ, ZS, SZ, SS skim like this:

1210
Becomes 0112 or 0121.

0112
Becomes 2101 or 1201.

2101
Becomes Flat or 1021 or 1210 or 1012.

1021
Becomes 2110 or 1210.

Others
For others mirror diagram and positions.

I piece
Alternate putting I piece on column 5 and 6 to reap tetrises. Borrow pieces if sides are too high.

This happens unlikely, but if center is too high, and you get many I pieces in a row, put them on the sides.

LJO pieces
Put them on the right side as advantegeous. Use gravity gun to change decision.