This is perhaps not the best example of a dissection of triangle and pentagon, but it is new and it does demonstrate the TT22 technique.
This is not a very elegant solution because of the rather small piece, but it is another example of a TT22 dissection. There are a number of different six piece solutions possible and this raises the question of whether or not a five piece solution exists. There is a range of rectangle shapes that will dissect to a pentagon in just five pieces, but I think it unlikely that anyone will find a five piece solution for the square.
Discovered by Harry Lindgren (1964).
I very nearly missed finding this dissection. The grey piece is so nearly cut into two, adding another two pieces to this dissection, that I did not think that it was possible. Fortunately I checked and hence obtained another record.
The overlay diagrams on the right show the basic dissection before I modify it to save some pieces.
There is room for improvement in this dissection. Is a 9 piece solution possible?
The top overlay diagram on the right shows the dissection before I modify it to save a piece.
The long triangle at the bottom left of the pentagon is in fact a quadrilateral with a short fourth side at the bottom.
This is another example of a TT22 dissection.
The thin spike makes this a rather inelegant dissection, but I have not been able to find another 9 piece solution.
Discovered by Greg Frederickson (1974).
Compared to the other dodecagram dissections this one is particularly inefficient. This is due to the dimensions of the pentagon making it impractical to form a pentagon tessellation that can overlay a dodecagram tessellation.
By turning over pieces we can improve the dissection, but a entirely different technique is required if the dissection is to be improved further.
Discovered by Harry Lindgren (1961).