Not all the towers along a transmission line are identical. Look closely at a tower where the line makes a sharp turn and you will likely find it is wider and beefier than other towers along the route. The added strength and weight are needed to resist the unbalanced pull of the conductors, which might overturn an ordinary tower. These special towers are called deviation or angle towers.
The transmission-line tower everybody knows is an Erector Set latticework of steel girders and diagonal braces. The techniques for designing and building these towers are the same ones used in constructing steel bridge trusses or crane booms. The individual pieces can be made cheaply from rolled steel and then bolted together on the site. This last point is more important than it might seem: transporting a fully assembled tower 100 feet tall is an awkward and expensive business.
But in the past couple of years, Brennan believes that tablets have caught up, with apps such as Apple’s ProCreate and Morpholio’s Trace becoming far more responsive to the user’s marks. “Tablets didn’t used to have that immediate response, from brain to eye to hand to pen to paper. A half-second delay has a huge impact on how you think — it causes you to stumble. But now that lag’s gone, it’s almost the same as drawing with pen on paper. You don’t need to engage with the airbrushes or other features — just use it in its purest form.” The stylus, too, far more convincingly apes a manual pen: “You’re able to tune it to almost replicate your favourite pen — and it doesn’t run out of ink.
Chetwood is an iPad devotee, using it to produce fantastical urban artworks as well as architecture. Far from hindering the drawing process, he believes tablets will give rise to a new era of creative drawing. “A lot of people say technology and computers are taking away the true art of drawing. That’s rubbish, it releases sketching. You can move so much quicker and change things much more quickly, and it keeps a record of what you’re doing. The control is just brilliant.” The polished glass surface is the only flaw, but textured acetates applied to the screen can make it feel more like paper.