Interesting! We now have a better idea where Jim's vague drawing of a box-shaped craft with a question mark may come from. He probably reluctantly made this sketch in Conrad's office after Zickler persuaded him. That explains why it is so vague, while the description of the craft in Halt's memo is much more accurate and describes a triangular craft.
Some excerpts from Clarke's page (emphasis mine):
One other significant thing happened on 28 December 1980. Maj Zickler finally convinced Sgt [James] Penniston to answer some questions for me. After a sincere guarantee that his report would have no ill effects on his career, Penniston reluctantly told his story. At the end of the session, I asked him to draw a picture of the object he had seen, which he did freehand. Jim Penniston is the only first-hand observer I was able to interview. We kept his name out of any of our correspondence to honour his request.
(...)
I asked [Penniston] for a description of the object. Penniston said he didn't get close enough for a detailed look. What he saw was generally rectangular in shape and slightly larger than a jeep in size. The object was mostly obscured by two horizontal rows of very bright closely spaced lights, one row white, the other light blue. He thought one row ran along the top, the other row around the middle. Again his distance from the object and the brightness of the lights obscured any further detailed observance. I am aware this description is at variance with subsequent statements and drawing made by others.
Here's Penniston's narrative to the best of my recollection. I'm paraphrasing, of course:
“….The lights were clearly visible when I arrived at the RAF Woodbridge gate. No one knew the source of the the lights, but some speculated that it was close enough to the approach path of the runway that it could in fact be a crashed plane. Because of this, it was decided that further investigation was warranted. Burroughs, Cabansag and myself were sent out by jeep. We worked our way toward the still- visible lights by way of a logging road. As we approached close enough to have a clear view of the site, [Burroughs?] decided we were close enough and stopped the vehicle. We were still more than 100 meters away and, wanting a better look, I decided to proceed further on foot. [Burroughs?] accompanied me as we closed on what we began to see was an object with lights on it. Our apprehension began to build,so we stopped about 50 meters away, taking cover behind some brush. After studying the situation for about 10 minutes, we decided to move in yet further for a closer look. Just as we began to close the distance to the object, it began to move away through the trees. The faster we moved toward it the faster it moved away. By the time we arrived at an open field a much greater distance had opened up between us,and soon it disappeared beyond a small rise in the direction of a farm house. After a short pause , we decided we had had enough and headed back toward [Cabansag] and the jeep. With a quick glance over the shoulder we saw the thing again back at the hill,this time coming toward us. We ran to get away, but within two seconds it was up and gone.-------(end of narrative)…”Jim's drawing, which includes the men taking cover behind some brush (at the bottom):
