<s>
Synthetic	B-Device
programming	I-Device
is	O
an	O
advanced	O
technique	O
for	O
programming	O
the	O
HP-41C	B-Device
and	O
Elektronika	B-Device
B3-34	I-Device
calculators	B-Application
,	O
involving	O
creating	O
instructions	O
(	O
or	O
combinations	O
of	O
instructions	O
and	O
operands	O
)	O
that	O
cannot	O
be	O
obtained	O
using	O
the	O
standard	O
capabilities	O
of	O
the	O
calculator	O
.	O
</s>
<s>
Some	O
HP-41C	B-Device
instructions	O
are	O
coded	O
in	O
memory	O
using	O
multiple	O
bytes	B-Application
.	O
</s>
<s>
Some	O
of	O
these	O
sequence	O
of	O
bytes	B-Application
correspond	O
to	O
instructions	O
the	O
calculator	O
is	O
able	O
to	O
execute	O
,	O
but	O
these	O
cannot	O
be	O
entered	O
in	O
the	O
program	O
memory	O
using	O
conventional	O
program	O
entry	O
methods	O
(	O
i.e.	O
</s>
<s>
Synthetic	B-Device
programming	I-Device
uses	O
a	O
bug	B-Error_Name
in	O
the	O
calculator	O
firmware	O
to	O
enter	O
those	O
byte	B-Application
sequences	O
as	O
a	O
sequence	O
of	O
other	O
instructions	O
,	O
then	O
partially	O
skipping	O
halfway	O
through	O
the	O
first	O
instruction	O
,	O
so	O
that	O
the	O
calculator	O
believes	O
the	O
end	O
of	O
the	O
first	O
instruction	O
is	O
actually	O
the	O
beginning	O
of	O
a	O
new	O
one	O
.	O
</s>
<s>
It	O
is	O
not	O
clear	O
if	O
the	O
creators	O
behind	O
the	O
HP-41	B-Device
were	O
aware	O
of	O
all	O
these	O
"	O
black	O
holes	O
"	O
.	O
</s>
