So I've got back into this. The first problem is that the cow graphic on the web page is too small. I tried trawling through the file system using Internalz to find the 'onboard' copy, but no joy. There is no search function that I can see. I tried using WOSQI to gain command line access and used the find command, but I don't know how to make it search subfolders and again I don't know where the graphic is to direct the search.
Is it possible to add file locations to the wiki? Either in the existing Legacy system or in the github repository? Just generic locations for groups of icons would be a start - I assume it's not all in one folder.
In the end, I kludged it. I sent myself a 'supercowpowers' email & made screen shots of the tumbling heffers. Of these, I spotted one that was nearly upright and it only required one degree of rotation to have it's feet on a flat line. I doubled the size without losing too much detail. I loaded this into Inkscape and after some messing around trying to work out what exactly was selected and how it worked, I have successfully made a trace and saved it in SVG format. This does not include the shadows or colour information, but I'm now reading on how to make multiple passes to improve the trace. I already checked and noted all colour values with an eyedropper tool, so I could do a set of B/W traces and add the colour back in, but it is possible to trace using colour as a parameter.
I'd guess that creating from scratch is probably easier than replication & last night started to measure a printout of the icon to discover the 'rules' of it's creation. You know, like Vitruvian Man, but with a cartoon cow! ;-) This might be interesting if I can learn more about how SVG's work, but it's a lot of effort for one icon, so I think tracing and fiddling with the output is the way to go for further work.
Another question: What warrants a layer? If system icons sit on a circle or a rhombus, then I suppose it makes sense that these common elements sit on layer one and the specific design on other layers, but are the any guidelines for separation of elements? For the cow, I'm thinking Body (with markings), Shadows, Feet, Head, Horns+Eyes+Nose, Head shadow. Too many? Not enough?