[Stiglr]

I think the general idea here was to make a 3 x 7 polygon because, if you count the number of spaces and shapes from top to bottom you get 7 "rows", and side to side, counting the border and the three shapes, you get 3 columns.

After making that basic 3 x 7, just move the vertices (in X and Y only) to the positions they need to go to describe the polygons, and then eliminate the "intervening" areas. If necessary, perhaps add vertices between pairs if there aren't enough to perfectly describe the shapes.

It's very simple. You just need to begin to think like the program, if that makes any sense.