Let's continue for 2K10 !
Game screen is composed of 8*5 blocks of 4*4 chars (8*8 pixies).Blocks are stored in memory in the same way as spritesexcept char pixies are always presents.
Per char :
*1 byte : flag , #36 = skipempty
*8 bytes : pixels in 1bit
There are 16 chars so 144 bytes per block
Levels are composed of columns of 5 blocks.The index first column of the first level bloc is located at #C4B1 (byte).The first column number 0 is located at (#C4BC)
A column address (word) can be computed like this : (column*5) + (#C4BC)