This is a relief cut patterns.
If you are not familiar with a relief cut here is a quick explanation. When you cut wood with a blade a small amount of wood is removed as dust. This is called the kerf. When that cut is made with the scroll saw table set at 90 degrees the piece will come out either direction. If you tilt the table and make the same cut the piece will come out one direction but be wedged the other direction. (Figure below)
We can take advantage of this to make the wood look as if it raised out of the board or sunk into the board.
The amount that the piece sinks into the board depends on the amount of angle the table is tilted and the thickness of the blade you make the cut with.
It often desirable to have the piece wedge in a certain direction. If you think of the piece as cork shaped you can visualize the direction it will go. The piece will move toward the small end.
If that seems difficult to visualize then just make test cuts with the same wood and blade until you get the desired effect. Confusing.
