|start with a 12"-long 1x4|
|cut an arrow head on one end|
|kerf angled cuts into the sides as shown|
|whack along the grain to remove excess between kerfs|
You can also sew small items to the strawbale walls by using a wood or plywood washer (as shown below). Make sure your twine wraps into the kerf cuts, and tie everything very tightly, so that the washer pulls into the face of the straw.
|wood or plywood "washer" for strawbale walls|