A few years ago, my brother Stephen, who is a Professor of Engineering at Sheffield University asked me to design front and back cover illustrations for a technical handbook, "The Little Book of Thermofluids" He specified a whimsical illustration of fire-fighters trying to extinguish a burning copy of the same book, using a completely inadequate hand-pump. The back cover shows the result of their effort.

Click image for larger version. 

Name:	old1.png 
Views:	268 
Size:	65.2 KB 
ID:	98230Click image for larger version. 

Name:	old2.png 
Views:	231 
Size:	68.1 KB 
ID:	98229

As you can see, I temporarily dropped a few of my self-imposed working rules, allowing myself the use of gradients, textures, shadows and outlines. My brother was very pleased with my illustrations.

Last year he revised the book and asked me to design new illustrations. For the front cover he suggested a "perpetual-motion waterfall" as made famous by M C Escher. I was a bit stumped as to how to draw this without just rehashing Escher's design. I tried a design using a bathtub and a rubber duck, but Stephen said it looked too cartoony; "it's NOT a children's book!".

Click image for larger version. 

Name:	draft2.gif 
Views:	229 
Size:	29.5 KB 
ID:	98228

Then I had the idea of using Sheffield landmarks. Not knowing the area well, I got him to suggest some suitable buildings. I then worked from photos that I found on line, using Xara's isometric grid, to produce drawings of St George's Church (now used as a lecture hall), the modernist Arts Tower and a polygonal structure called the Rotunda. Finally I added en endless watercourse connecting the buildings, along with a waterfall at the top of the church, a waterwheel and a pair of wires connecting the Arts Tower to the now lit-up Rotunda.

Click image for larger version. 

Name:	final_draft.png 
Views:	226 
Size:	170.4 KB 
ID:	98226

The back of the book features another physical impossibility. It's an electric car with a wind turbine on top. The faster it goes, the more power it generates and the faster it goes... I used feathering to give the impression of a 3-D model, but it's all drawn in Xara, again using the isometric grid.

Click image for larger version. 

Name:	Car - draft.png 
Views:	199 
Size:	33.5 KB 
ID:	98227