Mitered diamond panels are featured in this poncho. The pattern offers suggestions for alternate sleeve patterns.
The length is about 40” and could be even longer if blocked to its full stretch. Made for a tall person, so beware of its size. For a shorter person, say 5’5”, reduce the stitches of the first diamond.

Erratta: For triangle #2 pick up 36 stitches on the edge of first diamond.
Knit every row, and alternating yarns, and at the end of the rows on right SIDE
k2tog, K1.

An alternate sleeve version is now available and highly recommended. See my blog for complete details.

Some problems with the pattern link have been reported, so alternately at fibermania at g mail and I will send the pattern in an attachment.