Added pitch3, and an alert message to display the Number of turns, and the 3 other pitches.

// sP = pitch of first (bottom) full turn.
// eP = pitch of last (upper) full turn.

// p1 = initial instantaneous pitch, at bottom of curve.
// p2 = variable portion of pitch.
// p3 = terminal instantaneous pitch at top of curve.

I'm thinking that tangent lead angles would not change for various radii (?).

- Brian