Some of the curves in graffiti are arcs of spirals. The radius for the arc of a circle never changes, but the radius of a spiral arc changes as the arc moves from one endpoint to another. The rate of change is "delta" (d)

The short blue arc below is the arc of a circle. Its radius never changes, so d = 0. The longer blue arc is the arc of a spiral, with d = 0.5. Both have the same starting point, but because the second arc's radius keeps getting bigger, it ends up farther out.

How much farther out? We went through 125 degrees, and the radius increases by 0.5 units every degree, so the radius gained 125 * 0.5 = 62.5 units.

What part of this graffiti artist's body is the origin point? What part is the end of the radius? How far is the end of the radius from the orgin at the end of the arc? How can you calculate that using d?