Plot With Direction 3D

function [h1, h2] = plot_dir3 (vX, vY, vZ)
Plotting x-y-z variables with direction indicating vector to the next element.
Example
vX = linspace(0,2*pi, 10)';
vY = sin (vX);
vZ = cos (vX);
plot_dir3(vX, vY, vZ);