Halfway this morning I noticed strangely patterned numbers had appeared on the sidewalk next to my house. Also, a few arrows were hastily scribbled around it, one of them right next to my car. I'm assuming they are some kind of aerial recognition symbol or perhaps artillery adjusting scales, left behind by a recce patrol

.
Sadly any trace of them was long lost and what evidence remained was slowly obliterated by playing children. I managed to find an image that depicts the odd pattern. The investigation into its meaning is ongoing.
So, BNC, your agents seem to have finally located me. Took them longer than I expected.
BiteNibbleChomp wrote:Currently more focused on changing the Mk I tank icon (at the moment I have a black and white one that looks quite strange), so that I can replace the MkIVs in Arras 17 with decent Mk Is. Try and find an image that looks a bit more "head-on" like the mk IV (screens in earlier posts) that I could use?
Assuming you want a colour photograph of the real thing, the Bovington tank museum has the last semi-original Mark I (male), but it has been made part of a scenic display and those photos are unusable. I found one on the museum site however while
it is being transported.
Note that the barrels are fake (but the correct length). It also has no steering tail in this picture, they were quickly abandoned, but I'm not sure if you can 'shop one on. To be honest, I don't think most of the other differences between the Mark I and the Mark IV will be that noticable in the small icons. I checked my two (Osprey) books on the Mark I to Mark 4 and with the side-on viewing angle only the steering tail, roof rails, different sponson shape and barrel length will be visible. And the female tanks are even more similar. A question, if you don't mind: besides the units already in the beta, are you planning on adding more stuff that needs icons/photos? I might save you some time if I try to help finding them if you are looking for something in particular.
BTW, as a personal anecdote, I had a look around the insides of one of these,
this one, to be exact, and I got the impression these are about as dangerous to the crews as the Germans would have been. You had to be really brave to get inside one, it looks worse than a submarine. I told a fellow visitor how many people crewed it and pointed to some of their positions, his reaction was: "No way".
Oh, and next to the tank was
this little gem, and when I stuck my head inside I thought: Mmmh, that looks very tight for the occupant. Just looking at the picture on wikipedia won't give the proper effect, but try this: the doors were 135cm (little over 53in) tall, and the whole thing had about the same diameter, and in total is about as tall as a man. It is basically a small tank turret on a mini railroad track. Than I read the plaque and it said it was crewed by two...
Very nice museum BTW, they also had an interesting collection of strange WW1 military gear.