3 of 5: Closeup of the plaque on top. Birthday boy requested to have this equation on top, as he is studying engineering at uni. It is approximately equal to 21. You read the plaque as "Happy 21st Darren". Airbrushing on the letters and plaque. Plaque is on a 6inch cardboard.
The equation is very clever!
I assume it is correct too. I didn't go that far in my maths!