This expression links a pin from the puppet tool to a layer.
The pin automatically follows all the animation of the layer. The layer may also have parents.
Layer (Name or Index)
Name or index of the layer to which the puppet pin should be connected.
Layer Space Offset
Offset, in case the pin should not be linked to the anchor point of the layer but to another point in the layer space.
Comp Space Offset
Moves the link in composition space. For [100,0], for example, the pin is always 100 pixels right of the anchor point of the layer. In contrast to the Layer Space Offset, the Comp Space Offset is not affected by rotation or scale of the layer that the pin is linked to.