ternary_segments() is called it for its side-effects.
Arguments
x0, y0, z0
A numeric vector giving the x, y and z ternary
coordinates of points from which to draw.
...
Further graphical parameters (see graphics::par()) may also be
supplied as arguments, particularly, line type, lty, line width, lwd and
color, col. Also the line characteristics lend, ljoin and lmitre.
x1, y1, z1
A numeric vector giving the x, y and z ternary
coordinates of points to which to draw.