First you need fabric that don't ravel like knit or jersey fabric. Cut 1 x 1.5 m and fold in two as in the drawing.
Next grab your scissors and cut a 20 cm slit like the drawing shown.
Open the fabric, there should be two holes for your arms to go through. And you're done!
Wear it as a hooded vest or simply turn it upside down and wear it as a drape collar vest, each with many styling options. How's that for a versatile piece!