x_min  1
x_p0   1
x_p50  2.5
x_p100 b
x_max  b
y_min  1
y_p0   1
y_p50  3
y_p100 4
y_max  4
z_min  a
z_p0   a
z_p50  d
z_p100 f
z_max  f
