I found this site doing a search.
https://icebearquilts.wordpress.com/...ial-technique/
When I saw the first photo above of the pieced ones, they seem to have all the same center fabric and it looks like a version of the folded log cabin method. I have never heard of the Manx method, and it does look interesting--in the small scale pictured.
Not something I would want to try unless it would be a trivet near the microwave.