
Overstrike
==========

Original teletypes, which functioned much like a typewriter, did not have
features like bboolldd or u_n_d_e_r_l_i_n_e_ .  Instead, these were implemented by emitting
the BBAACCKKSSPPAACCEE character and then overstriking either another copy of the
character (for bboolldd) or the underscore character (for u_n_d_e_r_l_i_n_e_).  This gave
the effect of bboolldd or u_n_d_e_r_l_i_n_e_d_ text.

Amazingly, ddeeccaaddeess later, and this is still the mechanism that tools like
'm_a_n_' use to render bold and underlined text.
