As well as the pattern (written in US terms), this PDF contains additional information and resources that are not included in the blog post.

These include:

Printer friendly PDF document: Images and pattern are each on separate pages.

Full crochet chart of square

Exact amounts for each colour listed in metres and yards.

Alternative joining method: Invisible join (step by step photo instructions).

Getting an exact gauge is not critical but will affect yarn quantities and finished measurements.