Pelons are extremely rare "practice pieces" for the early t-shirt designs. Before production was initiated, the image or design was tested on cotton cloth or burlap to determine the color and line accuracy of the piece. Only a few of the "tests" were preserved once the design was deemed acceptable and the t-shirt went into production.
The Grateful Dead appeared at Fillmore West with New Riders of the Purple Sage, a Dead spin-off band, and Southern Comfort, a short-lived rock quintet. This was the last of four posters that David Singer drew for the Dead.