56. Altering the cursor
    ~~~~~~~~~~~~~~~~~~~
It is possible to alter the size and flash rate of the cursor in all screen
Modes, and to turn it off, with the command:

 VDU23;10,N,0;0;0;

where N is made up by adding together two numbers. The first controls the
flashrate, and you must pick one of the following...

 0=steady 32=invisible 64=fast_flash 96=slow_flash  (default is 96)

The second controls the size, and you may have anything from a thick block,
which is 0 in all Modes, to a thin line, which is 7 in Modes 0,1,2,4 & 5,
9 in Modes 3 & 6, and 18 in Mode 7, (default is 7 in Modes 0-6, and 18 in
Mode 7). ie.

 0=thick block in all modes
 7=thin line in modes 0,1,2,4,5  (default  7)
 9=thin line in modes 3,6        (default  7)
 8=thin line in mode 7           (default 18)

Thus N=105 (96+9) would give you a thinner cursor in Modes 3 & 6, and N=0
would give you a non-flashing solid block in all Modes. A Mode change will
reset the cursor, and it can still be turned on and off with the usual
commands.