Three values per graphic. First two are BYTEs and third is a WORD. The values are:

Offset	Meaning
0	Width (characters) or object flag
1	Height (characters) or terrain interaction flags
2	Memory address of graphic data (WORD)

All objects have height and width of two characters and this is encoded as a 255 value in the width field. The height field is then freed up to hold additional data, i.e. terrain interaction flags. As an object is composed of 4 character blocks in a 2 × 2 square, two bits can be allocated to the terrain interaction flags for each square individually. Only the two highest bits in the terrain interaction parameters are used, and these are bit 6 for preserve-attribute and bit 7 for impassable-vertically. Therefore the terrain interaction bits for object entries (used by the routine at 38539) are:

Offset	Meaning
7	Impassable-vertically (top-left character)
6	Preserve-attribute (top-left character)
5	Impassable-vertically (top-right character)
4	Preserve-attribute (top-right character)
3	Impassable-vertically (bottom-left character)
2	Preserve-attribute (bottom-left character)
1	Impassable-vertically (bottom-right character)
0	Preserve-attribute (bottom-right character)