Set up each base triangle with 5 stitches.
Tier 1 block: Pick up 5 stitches and continue until 2 stitches remain on the bottom triangle to which it attaches. Increase the number of rows in this block by skipping one 'attach' stitch (in this case p2tog). Essentially, a short row is employed to add 2 extra rows to the block. Continue to finish. Repeat for each block in the tier.
Tier 2 block: Now you're picking up stitches from the elongated blocks of tier 1. So pick up extra stitches accordingly. In this case, 6 (instead of 5). Use short row as before to add 2 extra rows to this widened block. Repeat for each block in the tier.
Tier 3 block: Pick up 6 stitches and elongate by 6 extra rows placing the short rows evenly.
Tier 4 block: Pick up (6+(6/2)), ie, 9 stitches and add 6 extra rows as in tier 3 blocks.
And so on. It takes 2 tiers to complete an increase. The first tier makes the blocks longer. The second makes them wider and you're done with that specific increase.
The woven fabric is simple but each 'band' radiates outwards in ever increasing size. This creates a spiraling effect.
The other method of creating bigger blocks are:
each tier: pick up n extra stitches and also elongate by nx2 rows. This would take 1 tier instead of 2 for a single step of increase.