I did something unheard of over the weekend as well - I read the SDK manual for the TI-83 Plus. Mainly because I was trying to work out how some of the function calls worked, but also the stuff they talk about with regards to applications (as opposed to programs - applications fill multiple 16KB pages of ROM on the calculator, programs are variable sizes and are copied to RAM location $9D93 for execution) was pretty interesting - and it sounds pretty nightmarish! I'll download some of the application development tools, see if I can puzzle them out and then try and recreate their behaviour in Brass. It's yet another output format - Brass can, with the .binarymode directive, switch between a number of binary output formats, including TI calculator formats (TI-73, TI-82, TI-83, TI-83+, TI-85, TI-86), raw binary and a number of hex text files (Intel, Intel word address, MOS technology and Motorola).
I'd never really understood how the LCD display driver worked on the TI-83 Plus, and the SDK documentation was pretty useful - even though I still can't quite work out why the X axis goes from top-to-bottom and the Y axis goes from left-to-right. It turns out direct access to the LCD can produce some very fast results... (and the world's worst greyscale):

Download binaries for TI-83/TI-83 Plus [Ion/MirageOS]
Yes, yes, I have a little 'something' about 3D tunnels.
the tunnel looks nice :)
EDIT: btw is the pattern generated with a few bits XORed?