It was his mood for the day. It was the temperature. The color of the ink. The color of the walls. The feel of the paper's grain. These dictated whether curly ques adorned the ps and qs or whether a quick line with a slash over top was made to represent his entire name.
A friend once remarked, "Suppose you become famous. How will anyone know whether or not an autograph of yours was authentic?" To this, Allister answered that, in general, he tried not to suppose. His signature was a part of him, an extension of him left behind for others. Why shouldn't those others know how he felt when he opened his first bank account on that particularly muggy day, August the third? Or when he proudly signed the petition for a natural park underneath his porch? Or when he closed the letter to his long lost pen pal whom he assumed to be living deep beneath the sea if at all?
Why practice a signature? Why plan how to loop the end of the d or the b one way when you may feel like simply drawing a line and darkly dotting one side of the bottom of it another day? To Allister, those learned ones who snickered behind the backs of an illiterate someone who carefully signed with an "X" may well have been snickering at themselves if they too were trapped by their own loops and crosses.
There was a signature for every time and place and Allister left it there.