vb.net Rectangles on a chess board

Rectangles on a chess board
I already have a video up that describes the number of squares on a chess board, but the mathematical conundrum of how many rectangles is one that I have never given any thought to. Before now.

I have looked at the maths explanation available on the web for this, but they didn't really help, so.....

There is no audio to this, and it does last a few minutes, but I have a datagridview consisting of 8 rows and 8 columns, marked out as a chess board.
The work that I have done is to show all possible rectangles, and yes, that does include all squares as well, since a square is a regular rectangle.
It starts at the beginning, and shows all 1x1 rectangles, then moves on to 1 row x 2 columns, then 3 columns, up to 8.
It then shows all 2 row occurrences, and on up to 8 rows, 1 column, then 8 rows x 2 columns etc.
It takes a few minutes, so unless you have anything more urgent, get a cuppa, and start it up...
At the end, there is a total shown, which, I am happy to say, agrees with the figure being quoted around the web!!!