PT dissections are created using a P strip and a T strip. But using T strips is not as straightforward as using P strips. Just overlaying the strips at the correct angle is not sufficient to give a dissection - try it! It is necessary the overlay the P strip so that its edges pass through the anchor points of the T strip. These anchor points are marked with small red dots.
So to dissect a pentagon to a dodecagon we first obtain strips for these two polygons:
These strips are now overlaid. Note how the edges of the dodecagon strip pass through the red anchor points of the pentagon strip. Since the blue anchor points play no role in these dissections, we will not show them below.
This gives the following dissection:
Below are some more examples of PT dissections.
In this example, one of the pieces is nearly cut in two. This piece is shown shaded to make clear that it is a single piece.