This is a free written crochet pattern on my crochet blog. Includes colour photos. Sample uses 10 colours, but can easily be used as a stash-buster. 9 colours - 100g of each and 200g of a 10th colour (this is also used for the border).

Gauge: 1 wide rectangle as per pattern for the first rectangle (6 rows with a starting chain of 23) = 14 cm x 4.5 cm, adjust hook size as necessary  Gauge is not critical for this project, but may affect yarn quantities.

Size can easily be adapted by adding more or less rows and columns.