color(color_types const t, const ex & i1, unsigned rl=0);
color(color_types const t, const ex & i1, const ex & i2, unsigned rl=0);
color(color_types const t, const ex & i1, const ex & i2, const ex & i3,
color(color_types const t, const ex & i1, unsigned rl=0);
color(color_types const t, const ex & i1, const ex & i2, unsigned rl=0);
color(color_types const t, const ex & i1, const ex & i2, const ex & i3,