The design goals for this stove were cheap materials and easy to build. Amazingly, its performance turned out to be very good. PASS stands for Plain And Simple Stove.
The original version had 21 holes for maximum airflow. That version sent a lot of flames up the side of the pot. I tried fewer holes to throttle back the flame a bit. In the 8-hole version, the boiling time is just a bit more while fuel consumption is considerably improved.
This stove is also documented as the main burner for my Girl Scout Stove Project.