if one starts with a 4x4 square in the center ( which will be replaced with the diagonals later)
draw a 4x4 square at each outside corner of that center squarr
then a 3x3 square on the outside corner of a 4x4 square
then a 5x5 square on the outside corne of a 3x3 sq
then a 2x2 square on the outside corner of. a 5x5 square
then a 6x6 square on the outside corner of a 2x2 square
then a 1x1 square on the outside corner of a 6x6 square
these squares form two diagonals that are the framework for the block.
I think the basis might be from six-sided dice
1 and 6 are on opposite sides of a die
2 and 5
3 and 4
then the rest is filled in.
I have no idez how to construct it as shown in the originsl drawing.