# test2

genfrac{left-delim}{right-delim}{thickness}{mathstyle}
{numerator}{denominator}      Like this:  [a+AB b-A^2]
[c-A^2 d+AB] Moving north-east A times produces:  .
Moving north-east A times produces: .
How to construct:
Start with any h-line: four squares along a horizontal line with , e.g. : Extend the arithmetic progressions along the diagonals: Then fill in a diagonal next to one of these 2, with any arithmetic progression. e.g: Then all the empty squares have been determined and can be filled in, making the sums equal across all line segments (the h-lines and v-lines).
Then when drawing the squaring, draw the squares of negative size on the other side of the line from where they ‘should’ be, e.g. : It seems that any grid of numbers constructed this way makes a tesselation of the plane.

Also, it seems that all the -sized squares (I mark them with a small circle on the squaring) lie in a straight line, no matter what sequences are used. I’m sure there’s an obvious reason for that! Unfortunately TikZ has too many bugs with barycentric plotting. ARGGHH! Unusable. Not slight – massive and weird errors. Nonregular CFs can also be represented as squares in a rectangle.    e.g.  Picture of : 1/(1+1/(1+1/(1+etc        