Star Blocks 101

My first star block.  Points match.  Dark and Light.  Looks good but is an 1 1/2" short. 

Light:  Cut 8 squares  3 7/8.                                 
Dark:  Cut 8 squares   3 7/8.                                   Make 1/2 square triangles.

Well folks:  I guess I ain't perfect.  I cut my lights and darks 4" and used a very scant quarter inch.

I ended up w/ a perfect 12 1/2 inch block.   Triangles need to be cut larger than directions say.  And then squared-up.