Mis-drop

A mis-drop is an unintentional tetromino placement. Mis-drops may or may not leave empty gaps on the playfield. Mis-drops that leave gaps can be fixed through several methods.

Garbage Method
Mis-drops can be treated as garbage. Build over the mis-drop and eliminate as many gaps as possible. Then, clear until you open the gap.

Twist Method
Certain mis-drops can be fixed with a simple twist.

In this diagram scenario, you can twist in a Z and slide a T under the overhang.

Surface Skimming
Sometimes, gaps created by mis-drops can be opened by clearing only the line(s) above it.